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http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #SNOBOL4 | SNOBOL4 | * # Define complex datatype
data('complex(r,i)')
* # Addition
define('addx(x1,x2)a,b,c,d') :(addx_end)
addx a = r(x1); b = i(x1); c = r(x2); d = i(x2)
addx = complex(a + c, b + d) :(return)
addx_end
* # Multiplication
define('multx(x1,x2)a,b,c,d') :(multx_end)
multx a = r(x1); b = i(x1); c = r(x2); d = i(x2)
multx = complex(a * c - b * d, b * c + a * d) :(return)
multx_end
* # Negation
define('negx(x)') :(negx_end)
negx negx = complex(-r(x), -i(x)) :(return)
negx_end
* # Inverse
define('invx(x)d') :(invx_end)
invx d = (r(x) * r(x)) + (i(x) * i(x))
invx = complex(1.0 * r(x) / d, 1.0 * -i(x) / d) :(return)
invx_end
* # Print compex number: a+bi / a-bi
define('printx(x)sign') :(printx_end)
printx sign = ge(i(x),0) '+'
printx = r(x) sign i(x) 'i' :(return)
printx_end
* # Test and display
a = complex(1,1)
b = complex(3.14159, 1.2)
output = printx( addx(a,b) )
output = printx( multx(a,b) )
output = printx( negx(a) ) ', ' printx( negx(b) )
output = printx( invx(a) ) ', ' printx( invx(b) )
end |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #Standard_ML | Standard ML |
(* Signature for complex numbers *)
signature COMPLEX = sig
type num
val complex : real * real -> num
val negative : num -> num
val plus : num -> num -> num
val minus : num -> num -> num
val times : num -> num -> num
val invert : num -> num
val print_number : num -> unit
end;
(* Actual implementation *)
structure Complex :> COMPLEX = struct
type num = real * real
fun complex (a, b) = (a, b)
fun negative (a, b) = (Real.~a, Real.~b)
fun plus (a1, b1) (a2, b2) = (Real.+ (a1, a2), Real.+(b1, b2))
fun minus i1 i2 = plus i1 (negative i2)
fun times (a1, b1) (a2, b2)= (Real.*(a1, a2) - Real.*(b1, b2), Real.*(a1, b2) + Real.*(a2, b1))
fun invert (a, b) =
let
val denom = a * a + b * b
in
(a / denom, ~b / denom)
end
fun print_number (a, b) =
print (Real.toString(a) ^ " + " ^ Real.toString(b) ^ "i\n")
end;
val i1 = Complex.complex(1.0,2.0); (* 1 + 2i *)
val i2 = Complex.complex(3.0,4.0); (* 3 + 4i *)
Complex.print_number(Complex.negative(i1)); (* -1 - 2i *)
Complex.print_number(Complex.plus i1 i2); (* 4 + 6i *)
Complex.print_number(Complex.minus i2 i1); (* 2 + 2i *)
Complex.print_number(Complex.times i1 i2); (* -5 + 10i *)
Complex.print_number(Complex.invert i1); (* 1/5 - 2i/5 *)
|
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #Pascal | Pascal | program ZToZ;
uses
math;
begin
write('0.0 ^ 0 :',IntPower(0.0,0):4:2);
writeln(' 0.0 ^ 0.0 :',Power(0.0,0.0):4:2);
end. |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #Perl | Perl | print 0 ** 0, "\n";
use Math::Complex;
print cplx(0,0) ** cplx(0,0), "\n"; |
http://rosettacode.org/wiki/Zebra_puzzle | Zebra puzzle | Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses.
The English man lives in the red house.
The Swede has a dog.
The Dane drinks tea.
The green house is immediately to the left of the white house.
They drink coffee in the green house.
The man who smokes Pall Mall has birds.
In the yellow house they smoke Dunhill.
In the middle house they drink milk.
The Norwegian lives in the first house.
The man who smokes Blend lives in the house next to the house with cats.
In a house next to the house where they have a horse, they smoke Dunhill.
The man who smokes Blue Master drinks beer.
The German smokes Prince.
The Norwegian lives next to the blue house.
They drink water in a house next to the house where they smoke Blend.
The question is, who owns the zebra?
Additionally, list the solution for all the houses.
Optionally, show the solution is unique.
Related tasks
Dinesman's multiple-dwelling problem
Twelve statements
| #D | D | import std.stdio, std.traits, std.algorithm, std.math;
enum Content { Beer, Coffee, Milk, Tea, Water,
Danish, English, German, Norwegian, Swedish,
Blue, Green, Red, White, Yellow,
Blend, BlueMaster, Dunhill, PallMall, Prince,
Bird, Cat, Dog, Horse, Zebra }
enum Test { Drink, Person, Color, Smoke, Pet }
enum House { One, Two, Three, Four, Five }
alias TM = Content[EnumMembers!Test.length][EnumMembers!House.length];
bool finalChecks(in ref TM M) pure nothrow @safe @nogc {
int diff(in Content a, in Content b, in Test ca, in Test cb)
nothrow @safe @nogc {
foreach (immutable h1; EnumMembers!House)
foreach (immutable h2; EnumMembers!House)
if (M[ca][h1] == a && M[cb][h2] == b)
return h1 - h2;
assert(0); // Useless but required.
}
with (Content) with (Test)
return abs(diff(Norwegian, Blue, Person, Color)) == 1 &&
diff(Green, White, Color, Color) == -1 &&
abs(diff(Horse, Dunhill, Pet, Smoke)) == 1 &&
abs(diff(Water, Blend, Drink, Smoke)) == 1 &&
abs(diff(Blend, Cat, Smoke, Pet)) == 1;
}
bool constrained(in ref TM M, in Test atest) pure nothrow @safe @nogc {
with (Content) with (Test) with (House)
final switch (atest) {
case Drink:
return M[Drink][Three] == Milk;
case Person:
foreach (immutable h; EnumMembers!House)
if ((M[Person][h] == Norwegian && h != One) ||
(M[Person][h] == Danish && M[Drink][h] != Tea))
return false;
return true;
case Color:
foreach (immutable h; EnumMembers!House)
if ((M[Person][h] == English && M[Color][h] != Red) ||
(M[Drink][h] == Coffee && M[Color][h] != Green))
return false;
return true;
case Smoke:
foreach (immutable h; EnumMembers!House)
if ((M[Color][h] == Yellow && M[Smoke][h] != Dunhill) ||
(M[Smoke][h] == BlueMaster && M[Drink][h] != Beer) ||
(M[Person][h] == German && M[Smoke][h] != Prince))
return false;
return true;
case Pet:
foreach (immutable h; EnumMembers!House)
if ((M[Person][h] == Swedish && M[Pet][h] != Dog) ||
(M[Smoke][h] == PallMall && M[Pet][h] != Bird))
return false;
return finalChecks(M);
}
}
void show(in ref TM M) {
foreach (h; EnumMembers!House) {
writef("%5s: ", h);
foreach (immutable t; EnumMembers!Test)
writef("%10s ", M[t][h]);
writeln;
}
}
void solve(ref TM M, in Test t, in size_t n) {
if (n == 1 && constrained(M, t)) {
if (t < 4) {
solve(M, [EnumMembers!Test][t + 1], 5);
} else {
show(M);
return;
}
}
foreach (immutable i; 0 .. n) {
solve(M, t, n - 1);
swap(M[t][n % 2 ? 0 : i], M[t][n - 1]);
}
}
void main() {
TM M;
foreach (immutable t; EnumMembers!Test)
foreach (immutable h; EnumMembers!House)
M[t][h] = EnumMembers!Content[t * 5 + h];
solve(M, Test.Drink, 5);
} |
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
| #E | E | ? def xml__quasiParser := <import:org.switchb.e.xml.makeXMLQuasiParser>()
> def xpath__quasiParser := xml__quasiParser.xPathQuasiParser()
> null
? def doc := xml`<inventory title="OmniCorp Store #45x10^3">
> <section name="health">
> <item upc="123456789" stock="12">
> <name>Invisibility Cream</name>
> <price>14.50</price>
> <description>Makes you invisible</description>
> </item>
> <item upc="445322344" stock="18">
> <name>Levitation Salve</name>
> <price>23.99</price>
> <description>Levitate yourself for up to 3 hours per application</description>n>
> </item>
> </section>
> <section name="food">
> <item upc="485672034" stock="653">
> <name>Blork and Freen Instameal</name>
> <price>4.95</price>
> <description>A tasty meal in a tablet; just add water</description>
> </item>
> <item upc="132957764" stock="44">
> <name>Grob winglets</name>
> <price>3.56</price>
> <description>Tender winglets of Grob. Just add water</description>
> </item>
> </section>
> </inventory>`
# value: xml`...`
? doc[xpath`inventory/section/item`][0]
# value: xml`<item stock="12" upc="123456789">
# <name>Invisibility Cream</name>
# <price>14.50</price>
# <description>Makes you invisible</description>
# </item>`
? for price in doc[xpath`inventory/section/item/price/text()`] { println(price :String) }
14.50
23.99
4.95
3.56
? doc[xpath`inventory/section/item/name`]
# value: [xml`<name>Invisibility Cream</name>`,
# xml`<name>Levitation Salve</name>`,
# xml`<name>Blork and Freen Instameal</name>`,
# xml`<name>Grob winglets</name>`]
|
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #Delphi | Delphi | procedure DrawYinAndYang(Canv: TCanvas; R: TRect);
begin
Canv.Brush.Color := clWhite;
Canv.Pen.Color := clWhite;
Canv.Pie(R.Left, R.Top, R.Right, R.Bottom,
(R.Right + R.Left) div 2, R.Top, (R.Right + R.Left) div 2, R.Bottom);
Canv.Brush.Color := clBlack;
Canv.Pen.Color := clBlack;
Canv.Pie(R.Left, R.Top, R.Right, R.Bottom,
(R.Right + R.Left) div 2, R.Bottom, (R.Right + R.Left) div 2, R.Top);
Canv.Brush.Color := clWhite;
Canv.Pen.Color := clWhite;
Canv.Ellipse((R.Right + 3 * R.Left) div 4, R.Top,
(3 * R.Right + R.Left) div 4, (R.Top + R.Bottom) div 2);
Canv.Brush.Color := clBlack;
Canv.Pen.Color := clBlack;
Canv.Ellipse((R.Right + 3 * R.Left) div 4, (R.Top + R.Bottom) div 2,
(3 * R.Right + R.Left) div 4, R.Bottom);
Canv.Brush.Color := clWhite;
Canv.Pen.Color := clWhite;
Canv.Ellipse((7 * R.Right + 9 * R.Left) div 16, (11 * R.Bottom + 5 * R.Top) div 16,
(9 * R.Right + 7 * R.Left) div 16, (13 * R.Bottom + 3 * R.Top) div 16);
Canv.Brush.Color := clBlack;
Canv.Pen.Color := clBlack;
Canv.Ellipse((7 * R.Right + 9 * R.Left) div 16, (3 * R.Bottom + 13 * R.Top) div 16,
(9 * R.Right + 7 * R.Left) div 16, (5 * R.Bottom + 11 * R.Top) div 16);
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
ClientWidth := 400;
ClientHeight := 400;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
R: TRect;
begin
R := ClientRect;
Canvas.Brush.Color := clGray;
Canvas.FillRect(R);
InflateRect(R, -50, -50);
OffsetRect(R, -40, -40);
DrawYinAndYang(Canvas, R);
InflateRect(R, -90, -90);
OffsetRect(R, 170, 170);
DrawYinAndYang(Canvas, R);
end;
|
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's state is used in the body of the function.
The Y combinator is itself a stateless function that, when applied to another stateless function, returns a recursive version of the function.
The Y combinator is the simplest of the class of such functions, called fixed-point combinators.
Task
Define the stateless Y combinator and use it to compute factorials and Fibonacci numbers from other stateless functions or lambda expressions.
Cf
Jim Weirich: Adventures in Functional Programming
| #CoffeeScript | CoffeeScript | Y = (f) -> g = f( (t...) -> g(t...) ) |
http://rosettacode.org/wiki/Zig-zag_matrix | Zig-zag matrix | Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to encode images).
For example, given 5, produce this array:
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24
Related tasks
Spiral matrix
Identity matrix
Ulam spiral (for primes)
See also
Wiktionary entry: anti-diagonals
| #CoffeeScript | CoffeeScript |
# Calculate a zig-zag pattern of numbers like so:
# 0 1 5
# 2 4 6
# 3 7 8
#
# There are many interesting ways to solve this; we
# try for an algebraic approach, calculating triangle
# areas, so that me minimize space requirements.
zig_zag_value = (x, y, n) ->
upper_triangle_zig_zag = (x, y) ->
# calculate the area of the triangle from the prior
# diagonals
diag = x + y
triangle_area = diag * (diag+1) / 2
# then add the offset along the diagonal
if diag % 2 == 0
triangle_area + y
else
triangle_area + x
if x + y < n
upper_triangle_zig_zag x, y
else
# For the bottom right part of the matrix, we essentially
# use reflection to count backward.
bottom_right_cell = n * n - 1
n -= 1
v = upper_triangle_zig_zag(n-x, n-y)
bottom_right_cell - v
zig_zag_matrix = (n) ->
row = (i) -> (zig_zag_value i, j, n for j in [0...n])
(row i for i in [0...n])
do ->
for n in [4..6]
console.log "---- n=#{n}"
console.log zig_zag_matrix(n)
console.log "\n"
|
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #REXX | REXX | /*REXX program calculates any number of terms in the Yellowstone (permutation) sequence.*/
parse arg m . /*obtain optional argument from the CL.*/
if m=='' | m=="," then m= 30 /*Not specified? Then use the default.*/
!.= 0 /*initialize an array of numbers(used).*/
# = 0 /*count of Yellowstone numbers in seq. */
$= /*list " " " " " */
do j=1 until #==m; prev= # - 1
if j<5 then do; #= #+1; @.#= j; !.#= j; !.j= 1; $= strip($ j); iterate; end
do k=1; if !.k then iterate /*Already used? Then skip this number.*/
if gcd(k, @.prev)<2 then iterate /*Not meet requirement? Then skip it. */
if gcd(k, @.#) \==1 then iterate /* " " " " " " */
#= #+1; @.#= k; !.k= 1; $= $ k /*bump ctr; assign; mark used; add list*/
leave /*find the next Yellowstone seq. number*/
end /*k*/
end /*j*/
say $ /*display a list of a Yellowstone seq. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
gcd: parse arg x,y; do until y==0; parse value x//y y with y x; end; return x |
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #Ring | Ring |
see "working..." + nl
row = 3
num = 2
numbers = 1:51
first = 2
second = 3
see "Yellowstone numbers are:" + nl
see "1 " + first + " " + second + " "
for n = 4 to len(numbers)
flag1 = 1
flag2 = 1
if first < numbers[n]
min = first
else
min = numbers[n]
ok
for m = 2 to min
if first%m = 0 and numbers[n]%m = 0
flag1 = 0
exit
ok
next
if second < numbers[n]
min = second
else
min = numbers[n]
ok
for m = 2 to min
if second%m = 0 and numbers[n]%m = 0
flag2 = 0
exit
ok
next
if flag1 = 0 and flag2 = 1
see "" + numbers[n] + " "
first = second
second = numbers[n]
del(numbers,n)
row = row+1
if row%10 = 0
see nl
ok
num = num + 1
if num = 29
exit
ok
n = 3
ok
next
see "Found " + row + " Yellowstone numbers" + nl
see "done..." + nl
|
http://rosettacode.org/wiki/Yahoo!_search_interface | Yahoo! search interface | Create a class for searching Yahoo! results.
It must implement a Next Page method, and read URL, Title and Content from results.
| #Raku | Raku |
use Gumbo;
use LWP::Simple;
use XML::Text;
class YahooSearch {
has $!dom;
submethod BUILD (:$!dom) { }
method new($term) {
self.bless(
dom => parse-html(
LWP::Simple.get("http://search.yahoo.com/search?p={ $term }")
)
);
}
method next {
$!dom = parse-html(
LWP::Simple.get(
$!dom.lookfor( TAG => 'a', class => 'next' ).head.attribs<href>
)
);
self;
}
method text ($node) {
return '' unless $node;
return $node.text if $node ~~ XML::Text;
$node.nodes.map({ self.text($_).trim }).join(' ');
}
method results {
state $n = 0;
for $!dom.lookfor( TAG => 'h3', class => 'title') {
given .lookfor( TAG => 'a' )[0] {
next unless $_; # No Link
next if .attribs<href> ~~ / ^ 'https://r.search.yahoo.com' /; # Ad
say "=== #{ ++$n } ===";
say "Title: { .contents[0] ?? self.text( .contents[0] ) !! '' }";
say " URL: { .attribs<href> }";
my $pt = .parent.parent.parent.elements( TAG => 'div' ).tail;
say " Text: { self.text($pt) }";
}
}
self;
}
}
sub MAIN (Str $search-term) is export {
YahooSearch.new($search-term).results.next.results;
}
|
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | s:=ToString[5^4^3^2];
Print[StringTake[s,20]<>"..."<>StringTake[s,-20]<>" ("<>ToString@StringLength@s<>" digits)"]; |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #MATLAB | MATLAB | >> answer = vpi(5)^(vpi(4)^(vpi(3)^vpi(2)));
>> numDigits = order(answer) + 1
numDigits =
183231
>> [sprintf('%d',leadingdigit(answer,20)) '...' sprintf('%d',trailingdigit(answer,20))]
%First and Last 20 Digits
ans =
62060698786608744707...92256259918212890625 |
http://rosettacode.org/wiki/Zeckendorf_number_representation | Zeckendorf number representation | Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series.
Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, 5, 8, 13.
The decimal number eleven can be written as 0*13 + 1*8 + 0*5 + 1*3 + 0*2 + 0*1 or 010100 in positional notation where the columns represent multiplication by a particular member of the sequence. Leading zeroes are dropped so that 11 decimal becomes 10100.
10100 is not the only way to make 11 from the Fibonacci numbers however; 0*13 + 1*8 + 0*5 + 0*3 + 1*2 + 1*1 or 010011 would also represent decimal 11. For a true Zeckendorf number there is the added restriction that no two consecutive Fibonacci numbers can be used which leads to the former unique solution.
Task
Generate and show here a table of the Zeckendorf number representations of the decimal numbers zero to twenty, in order.
The intention in this task to find the Zeckendorf form of an arbitrary integer. The Zeckendorf form can be iterated by some bit twiddling rather than calculating each value separately but leave that to another separate task.
Also see
OEIS A014417 for the the sequence of required results.
Brown's Criterion - Numberphile
Related task
Fibonacci sequence
| #Pascal | Pascal |
program ZeckendorfRep_RC;
{$mode objfpc}{$H+}
uses SysUtils;
// Return Zeckendorf representation of the passed-in cardinal.
function ZeckRep( C : cardinal) : string;
var
a, b, rem : cardinal;
j, nrDigits: integer;
begin
// Case C = 0 has to be treated specially
if (C = 0) then begin
result := '0';
exit;
end;
// Find largest Fibonacci number not exceeding C
a := 1;
b := 1;
nrDigits := 1;
rem := C - 1;
while (rem >= b) do begin
dec( rem, b);
inc( a, b);
b := a - b;
inc( nrDigits);
end;
// Fill in digits by reversing Fibonacci back to start
SetLength( result, nrDigits);
j := 1;
result[j] := '1';
for j := 2 to nrDigits do begin
if (rem >= b) then begin
dec( rem, b);
result[j] := '1';
end
else result[j] := '0';
b := a - b;
dec( a, b);
end;
// Assert((a = 1) and (b = 1)); // optional check
end;
// Main routine
var
C : cardinal;
begin
for C := 1 to 20 do
WriteLn( SysUtils.Format( '%2d: %s', [C, ZeckRep(C)]));
end.
|
http://rosettacode.org/wiki/100_doors | 100 doors | There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6, ...), and toggle it.
The third time, visit every 3rd door (door #3, #6, #9, ...), etc, until you only visit the 100th door.
Task
Answer the question: what state are the doors in after the last pass? Which are open, which are closed?
Alternate:
As noted in this page's discussion page, the only doors that remain open are those whose numbers are perfect squares.
Opening only those doors is an optimization that may also be expressed;
however, as should be obvious, this defeats the intent of comparing implementations across programming languages.
| #Common_Lisp | Common Lisp | (defun visit-door (doors doornum value1 value2)
"visits a door, swapping the value1 to value2 or vice-versa"
(let ((d (copy-list doors))
(n (- doornum 1)))
(if (eql (nth n d) value1)
(setf (nth n d) value2)
(setf (nth n d) value1))
d))
(defun visit-every (doors num iter value1 value2)
"visits every 'num' door in the list"
(if (> (* iter num) (length doors))
doors
(visit-every (visit-door doors (* num iter) value1 value2)
num
(+ 1 iter)
value1
value2)))
(defun do-all-visits (doors cnt value1 value2)
"Visits all doors changing the values accordingly"
(if (< cnt 1)
doors
(do-all-visits (visit-every doors cnt 1 value1 value2)
(- cnt 1)
value1
value2)))
(defun print-doors (doors)
"Pretty prints the doors list"
(format T "~{~A ~A ~A ~A ~A ~A ~A ~A ~A ~A~%~}~%" doors))
(defun start (&optional (size 100))
"Start the program"
(let* ((open "_")
(shut "#")
(doors (make-list size :initial-element shut)))
(print-doors (do-all-visits doors size open shut)))) |
http://rosettacode.org/wiki/Arrays | Arrays | This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retrieve an element (if available, show both fixed-length arrays and
dynamic arrays, pushing a value into it).
Please discuss at Village Pump: Arrays.
Please merge code in from these obsolete tasks:
Creating an Array
Assigning Values to an Array
Retrieving an Element of an Array
Related tasks
Collections
Creating an Associative Array
Two-dimensional array (runtime)
| #Go | Go | package main
import (
"fmt"
)
func main() {
// creates an array of five ints.
// specified length must be a compile-time constant expression.
// this allows compiler to do efficient bounds checking.
var a [5]int
// since length is compile-time constant, len() is a compile time constant
// and does not have the overhead of a function call.
fmt.Println("len(a) =", len(a))
// elements are always initialized to 0
fmt.Println("a =", a)
// assign a value to an element. indexing is 0 based.
a[0] = 3
fmt.Println("a =", a)
// retrieve element value with same syntax
fmt.Println("a[0] =", a[0])
// a slice references an underlying array
s := a[:4] // this does not allocate new array space.
fmt.Println("s =", s)
// slices have runtime established length and capacity, but len() and
// cap() are built in to the compiler and have overhead more like
// variable access than function call.
fmt.Println("len(s) =", len(s), " cap(s) =", cap(s))
// slices can be resliced, as long as there is space
// in the underlying array.
s = s[:5]
fmt.Println("s =", s)
// s still based on a
a[0] = 22
fmt.Println("a =", a)
fmt.Println("s =", s)
// append will automatically allocate a larger underlying array as needed.
s = append(s, 4, 5, 6)
fmt.Println("s =", s)
fmt.Println("len(s) =", len(s), " cap(s) =", cap(s))
// s no longer based on a
a[4] = -1
fmt.Println("a =", a)
fmt.Println("s =", s)
// make creates a slice and allocates a new underlying array
s = make([]int, 8)
fmt.Println("s =", s)
fmt.Println("len(s) =", len(s), " cap(s) =", cap(s))
// the cap()=10 array is no longer referenced
// and would be garbage collected eventually.
} |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #Stata | Stata | mata
C(2,3)
2 + 3i
a=2+3i
b=1-2*i
a+b
-5 + 3i
a-b
9 + 3i
a*b
-14 - 21i
a/b
-.285714286 - .428571429i
-a
-2 - 3i
1/a
.153846154 - .230769231i
conj(a)
2 - 3i
abs(a)
3.605551275
arg(a)
.9827937232
exp(a)
-7.31511009 + 1.04274366i
log(a)
1.28247468 + .982793723i
end |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #Swift | Swift |
public struct Complex {
public let real : Double
public let imaginary : Double
public init(real inReal:Double, imaginary inImaginary:Double) {
real = inReal
imaginary = inImaginary
}
public static var i : Complex = Complex(real:0, imaginary: 1)
public static var zero : Complex = Complex(real: 0, imaginary: 0)
public var negate : Complex {
return Complex(real: -real, imaginary: -imaginary)
}
public var invert : Complex {
let d = (real*real + imaginary*imaginary)
return Complex(real: real/d, imaginary: -imaginary/d)
}
public var conjugate : Complex {
return Complex(real: real, imaginary: -imaginary)
}
}
public func + (left: Complex, right: Complex) -> Complex {
return Complex(real: left.real+right.real, imaginary: left.imaginary+right.imaginary)
}
public func * (left: Complex, right: Complex) -> Complex {
return Complex(real: left.real*right.real - left.imaginary*right.imaginary,
imaginary: left.real*right.imaginary+left.imaginary*right.real)
}
public prefix func - (right:Complex) -> Complex {
return right.negate
}
// Checking equality is almost necessary for a struct of this type to be useful
extension Complex : Equatable {}
public func == (left:Complex, right:Complex) -> Bool {
return left.real == right.real && left.imaginary == right.imaginary
}
|
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #Phix | Phix | ?power(0,0)
requires("0.8.4") -- (now fixed/crashes on earlier versions)
include complex.e
complex a = complex_new(0,0),
b = complex_power(a,a)
string sa = complex_sprint(a,true),
sb = complex_sprint(b,true)
printf(1,"%s ^ %s = %s\n",{sa,sa,sb})
|
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #Phixmonti | Phixmonti | def mypower
dup not if
. sign dup 0 == if . 1 endif
else
power
endif
enddef
0 0 mypower print |
http://rosettacode.org/wiki/Zebra_puzzle | Zebra puzzle | Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses.
The English man lives in the red house.
The Swede has a dog.
The Dane drinks tea.
The green house is immediately to the left of the white house.
They drink coffee in the green house.
The man who smokes Pall Mall has birds.
In the yellow house they smoke Dunhill.
In the middle house they drink milk.
The Norwegian lives in the first house.
The man who smokes Blend lives in the house next to the house with cats.
In a house next to the house where they have a horse, they smoke Dunhill.
The man who smokes Blue Master drinks beer.
The German smokes Prince.
The Norwegian lives next to the blue house.
They drink water in a house next to the house where they smoke Blend.
The question is, who owns the zebra?
Additionally, list the solution for all the houses.
Optionally, show the solution is unique.
Related tasks
Dinesman's multiple-dwelling problem
Twelve statements
| #EchoLisp | EchoLisp |
(lib 'hash)
(lib 'amb)
;; return #f or house# for thing/category
;; houses := (0 1 2 3 4)
(define (house-get H category thing houses)
(for/or ((i houses)) #:continue (!equal? (hash-ref (vector-ref H i) category) thing)
i))
;; return house # for thing (eg cat) in category (eq animals)
;; add thing if not already here
(define-syntax-rule (house-set thing category)
(or
(house-get H 'category 'thing houses)
(dispatch H 'category 'thing context houses )))
;; we know that thing/category is in a given house
(define-syntax-rule (house-force thing category house)
(dispatch H 'category 'thing context houses house))
;; return house# or fail if impossible
(define (dispatch H category thing context houses (forced #f))
(define house (or forced (amb context houses))) ;; get a house number
(when (hash-ref (vector-ref H house) category) (amb-fail)) ;; fail if occupied
(hash-set (vector-ref H house) category thing) ;; else remember house contents
house)
(define (house-next h1 h2)
(amb-require (or (= h1 (1+ h2)) (= h1 (1- h2)))))
(define (zebra-puzzle context houses )
(define H (build-vector 5 make-hash)) ;; house[i] := hash(category) -> thing
; In the middle house they drink milk.
(house-force milk drinks 2)
;The Norwegian lives in the first house.
(house-force norvegian people 0)
; The English man lives in the red house.
(house-force red colors(house-set english people))
; The Swede has a dog.
(house-force dog animals (house-set swede people))
; The Dane drinks tea.
(house-force tea drinks (house-set dane people))
; The green house is immediately to the left of the white house.
(amb-require (= (house-set green colors) (1- (house-set white colors))))
; They drink coffee in the green house.
(house-force coffee drinks (house-set green colors))
; The man who smokes Pall Mall has birds.
(house-force birds animals (house-set pallmall smoke))
; In the yellow house they smoke Dunhill.
(house-force dunhill smoke (house-set yellow colors))
; The Norwegian lives next to the blue house.
(house-next (house-set norvegian people) (house-set blue colors))
; The man who smokes Blend lives in the house next to the house with cats.
(house-next (house-set blend smoke) (house-set cats animals))
; In a house next to the house where they have a horse, they smoke Dunhill.
(house-next (house-set horse animals) (house-set dunhill smoke))
; The man who smokes Blue Master drinks beer.
(house-force beer drinks (house-set bluemaster smoke))
; The German smokes Prince.
(house-force prince smoke (house-set german people))
; They drink water in a house next to the house where they smoke Blend.
(house-next (house-set water drinks) (house-set blend smoke))
;; Finally .... the zebra 🐴
(house-set 🐴 animals)
(for ((i houses))
(writeln i (hash-values (vector-ref H i))))
(writeln '----------)
(amb-fail) ;; will ensure ALL solutions are printed
)
|
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
| #Erlang | Erlang |
-module(xml_xpath).
-include_lib("xmerl/include/xmerl.hrl").
-export([main/0]).
main() ->
XMLDocument =
"<inventory title=\"OmniCorp Store #45x10^3\">
<section name=\"health\">
<item upc=\"123456789\" stock=\"12\">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc=\"445322344\" stock=\"18\">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name=\"food\">
<item upc=\"485672034\" stock=\"653\">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc=\"132957764\" stock=\"44\">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>",
{Document,_} = xmerl_scan:string(XMLDocument),
io:format("First item:\n~s\n",
[lists:flatten(
xmerl:export_simple(
[hd(xmerl_xpath:string("//item[1]", Document))],
xmerl_xml, [{prolog, ""}]))]),
io:format("Prices:\n"),
[ io:format("~s\n",[Content#xmlText.value])
|| #xmlElement{content = [Content|_]} <- xmerl_xpath:string("//price", Document)],
io:format("Names:\n"),
[ Content#xmlText.value
|| #xmlElement{content = [Content|_]} <- xmerl_xpath:string("//name", Document)].
|
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #DWScript | DWScript | type
TColorFuncX = function (x : Integer) : Integer;
type
TSquareBoard = class
Scale : Integer;
Pix : array of array of Integer;
constructor Create(aScale : Integer);
begin
Scale := aScale;
Pix := new Integer[aScale*12+1, aScale*12+1];
end;
method Print;
begin
var i, j : Integer;
for i:=0 to Pix.High do begin
for j:=0 to Pix.High do begin
case Pix[j, i] of
1 : Print('.');
2 : Print('#');
else
Print(' ');
end;
end;
PrintLn('');
end;
end;
method DrawCircle(cx, cy, cr : Integer; color : TColorFuncX);
begin
var rr := Sqr(cr*Scale);
var x, y : Integer;
for x := 0 to Pix.High do begin
for y := 0 to Pix.High do begin
if Sqr(x-cx*Scale)+Sqr(y-cy*Scale)<=rr then
Pix[x, y] := color(x);
end;
end;
end;
method ColorHalf(x : Integer) : Integer;
begin
if (x<6*Scale) then
Result:=1
else Result:=2;
end;
method ColorYin(x : Integer) : Integer;
begin
Result:=2;
end;
method ColorYang(x : Integer) : Integer;
begin
Result:=1;
end;
method YinYang;
begin
DrawCircle(6, 6, 6, ColorHalf);
DrawCircle(6, 3, 3, ColorYang);
DrawCircle(6, 9, 3, ColorYin);
DrawCircle(6, 9, 1, ColorYang);
DrawCircle(6, 3, 1, ColorYin);
end;
end;
var sq := new TSquareBoard(2);
sq.YinYang;
sq.Print;
sq := new TSquareBoard(1);
sq.YinYang;
sq.Print; |
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's state is used in the body of the function.
The Y combinator is itself a stateless function that, when applied to another stateless function, returns a recursive version of the function.
The Y combinator is the simplest of the class of such functions, called fixed-point combinators.
Task
Define the stateless Y combinator and use it to compute factorials and Fibonacci numbers from other stateless functions or lambda expressions.
Cf
Jim Weirich: Adventures in Functional Programming
| #Common_Lisp | Common Lisp | (defun Y (f)
((lambda (g) (funcall g g))
(lambda (g)
(funcall f (lambda (&rest a)
(apply (funcall g g) a))))))
(defun fac (n)
(funcall
(Y (lambda (f)
(lambda (n)
(if (zerop n)
1
(* n (funcall f (1- n)))))))
n))
(defun fib (n)
(funcall
(Y (lambda (f)
(lambda (n a b)
(if (< n 1)
a
(funcall f (1- n) b (+ a b))))))
n 0 1))
? (mapcar #'fac '(1 2 3 4 5 6 7 8 9 10))
(1 2 6 24 120 720 5040 40320 362880 3628800))
? (mapcar #'fib '(1 2 3 4 5 6 7 8 9 10))
(1 1 2 3 5 8 13 21 34 55) |
http://rosettacode.org/wiki/Zig-zag_matrix | Zig-zag matrix | Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to encode images).
For example, given 5, produce this array:
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24
Related tasks
Spiral matrix
Identity matrix
Ulam spiral (for primes)
See also
Wiktionary entry: anti-diagonals
| #Common_Lisp | Common Lisp | (defun zigzag (n)
(flet ((move (i j)
(if (< j (1- n))
(values (max 0 (1- i)) (1+ j))
(values (1+ i) j))))
(loop with a = (make-array (list n n) :element-type 'integer)
with x = 0
with y = 0
for v from 0 below (* n n)
do (setf (aref a x y) v)
(if (evenp (+ x y))
(setf (values x y) (move x y))
(setf (values y x) (move y x)))
finally (return a)))) |
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #Ruby | Ruby | def yellow(n)
a = [1, 2, 3]
b = { 1 => true, 2 => true, 3 => true }
i = 4
while n > a.length
if !b[i] && i.gcd(a[-1]) == 1 && i.gcd(a[-2]) > 1
a << i
b[i] = true
i = 4
end
i += 1
end
a
end
p yellow(30) |
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #Rust | Rust | // [dependencies]
// num = "0.3"
// plotters = "^0.2.15"
use num::integer::gcd;
use plotters::prelude::*;
use std::collections::HashSet;
fn yellowstone_sequence() -> impl std::iter::Iterator<Item = u32> {
let mut sequence: HashSet<u32> = HashSet::new();
let mut min = 1;
let mut n = 0;
let mut n1 = 0;
let mut n2 = 0;
std::iter::from_fn(move || {
n2 = n1;
n1 = n;
if n < 3 {
n += 1;
} else {
n = min;
while !(!sequence.contains(&n) && gcd(n1, n) == 1 && gcd(n2, n) > 1) {
n += 1;
}
}
sequence.insert(n);
while sequence.contains(&min) {
sequence.remove(&min);
min += 1;
}
Some(n)
})
}
// Based on the example in the "Quick Start" section of the README file for
// the plotters library.
fn plot_yellowstone(filename: &str) -> Result<(), Box<dyn std::error::Error>> {
let root = BitMapBackend::new(filename, (800, 600)).into_drawing_area();
root.fill(&WHITE)?;
let mut chart = ChartBuilder::on(&root)
.caption("Yellowstone Sequence", ("sans-serif", 24).into_font())
.margin(10)
.x_label_area_size(20)
.y_label_area_size(20)
.build_ranged(0usize..100usize, 0u32..180u32)?;
chart.configure_mesh().draw()?;
chart.draw_series(LineSeries::new(
yellowstone_sequence().take(100).enumerate(),
&BLUE,
))?;
Ok(())
}
fn main() {
println!("First 30 Yellowstone numbers:");
for y in yellowstone_sequence().take(30) {
print!("{} ", y);
}
println!();
match plot_yellowstone("yellowstone.png") {
Ok(()) => {}
Err(error) => eprintln!("Error: {}", error),
}
} |
http://rosettacode.org/wiki/Yahoo!_search_interface | Yahoo! search interface | Create a class for searching Yahoo! results.
It must implement a Next Page method, and read URL, Title and Content from results.
| #Ruby | Ruby | require 'open-uri'
require 'hpricot'
SearchResult = Struct.new(:url, :title, :content)
class SearchYahoo
@@urlinfo = [nil, 'ca.search.yahoo.com', 80, '/search', nil, nil]
def initialize(term)
@term = term
@page = 1
@results = nil
@url = URI::HTTP.build(@@urlinfo)
end
def next_result
if not @results
@results = []
fetch_results
elsif @results.empty?
next_page
end
@results.shift
end
def fetch_results
@url.query = URI.escape("p=%s&b=%d" % [@term, @page])
doc = open(@url) { |f| Hpricot(f) }
parse_html(doc)
end
def next_page
@page += 10
fetch_results
end
def parse_html(doc)
doc.search("div#main").search("div").each do |div|
next unless div.has_attribute?("class") and div.get_attribute("class").index("res") == 0
result = SearchResult.new
div.search("a").each do |link|
next unless link.has_attribute?("class") and link.get_attribute("class") == "yschttl spt"
result.url = link.get_attribute("href")
result.title = link.inner_text
end
div.search("div").each do |abstract|
next unless abstract.has_attribute?("class") and abstract.get_attribute("class").index("abstr")
result.content = abstract.inner_text
end
@results << result
end
end
end
s = SearchYahoo.new("test")
15.times do |i|
result = s.next_result
puts i+1
puts result.title
puts result.url
puts result.content
puts
end |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #Maxima | Maxima | block([s, n], s: string(5^4^3^2), n: slength(s), print(substring(s, 1, 21), "...", substring(s, n - 19)), n);
/* 62060698786608744707...92256259918212890625
183231 */ |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #Nanoquery | Nanoquery | value = str(5^(4^(3^2)))
first20 = value.substring(0,20)
last20 = value.substring(len(value) - 20)
println "The first twenty digits are " + first20
println "The last twenty digits are " + last20
if (first20 = "62060698786608744707") && (last20 = "92256259918212890625")
println "\nThese digits are correct.\n"
end
println "The result is " + len(str(value)) + " digits long" |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #Nemerle | Nemerle | using System.Console;
using System.Numerics;
using System.Numerics.BigInteger;
module BigInt
{
Main() : void
{
def n = Pow(5, Pow(4, Pow(3, 2) :> int) :> int).ToString();
def len = n.Length;
def first20 = n.Substring(0, 20);
def last20 = n.Substring(len - 20, 20);
assert (first20 == "62060698786608744707", "High order digits are incorrect");
assert (last20 == "92256259918212890625", "Low order digits are incorrect");
assert (len == 183231, "Result contains wrong number of digits");
WriteLine("Result: {0} ... {1}", first20, last20);
WriteLine($"Length of result: $len digits");
}
} |
http://rosettacode.org/wiki/Zeckendorf_number_representation | Zeckendorf number representation | Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series.
Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, 5, 8, 13.
The decimal number eleven can be written as 0*13 + 1*8 + 0*5 + 1*3 + 0*2 + 0*1 or 010100 in positional notation where the columns represent multiplication by a particular member of the sequence. Leading zeroes are dropped so that 11 decimal becomes 10100.
10100 is not the only way to make 11 from the Fibonacci numbers however; 0*13 + 1*8 + 0*5 + 0*3 + 1*2 + 1*1 or 010011 would also represent decimal 11. For a true Zeckendorf number there is the added restriction that no two consecutive Fibonacci numbers can be used which leads to the former unique solution.
Task
Generate and show here a table of the Zeckendorf number representations of the decimal numbers zero to twenty, in order.
The intention in this task to find the Zeckendorf form of an arbitrary integer. The Zeckendorf form can be iterated by some bit twiddling rather than calculating each value separately but leave that to another separate task.
Also see
OEIS A014417 for the the sequence of required results.
Brown's Criterion - Numberphile
Related task
Fibonacci sequence
| #Perl | Perl | my @fib;
sub fib {
my $n = shift;
return 1 if $n < 2;
return $fib[$n] //= fib($n-1)+fib($n-2);
}
sub zeckendorf {
my $n = shift;
return "0" unless $n;
my $i = 1;
$i++ while fib($i) <= $n;
my $z = '';
while( --$i ) {
$z .= "0", next if fib( $i ) > $n;
$z .= "1";
$n -= fib( $i );
}
return $z;
}
printf "%4d: %8s\n", $_, zeckendorf($_) for 0..20;
|
http://rosettacode.org/wiki/100_doors | 100 doors | There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6, ...), and toggle it.
The third time, visit every 3rd door (door #3, #6, #9, ...), etc, until you only visit the 100th door.
Task
Answer the question: what state are the doors in after the last pass? Which are open, which are closed?
Alternate:
As noted in this page's discussion page, the only doors that remain open are those whose numbers are perfect squares.
Opening only those doors is an optimization that may also be expressed;
however, as should be obvious, this defeats the intent of comparing implementations across programming languages.
| #Component_Pascal | Component Pascal |
MODULE Doors100;
IMPORT StdLog;
PROCEDURE Do*;
VAR
i,j: INTEGER;
closed: ARRAY 101 OF BOOLEAN;
BEGIN
(* initialization of closed to true *)
FOR i := 0 TO LEN(closed) - 1 DO closed[i] := TRUE END;
(* process *)
FOR i := 1 TO LEN(closed) DO;
j := 1;
WHILE j < LEN(closed) DO
IF j MOD i = 0 THEN closed[j] := ~closed[j] END;INC(j)
END
END;
(* print results *)
i := 1;
WHILE i < LEN(closed) DO
IF (i - 1) MOD 10 = 0 THEN StdLog.Ln END;
IF closed[i] THEN StdLog.String("C ") ELSE StdLog.String("O ") END;
INC(i)
END;
END Do;
END Doors100.
|
http://rosettacode.org/wiki/Arrays | Arrays | This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retrieve an element (if available, show both fixed-length arrays and
dynamic arrays, pushing a value into it).
Please discuss at Village Pump: Arrays.
Please merge code in from these obsolete tasks:
Creating an Array
Assigning Values to an Array
Retrieving an Element of an Array
Related tasks
Collections
Creating an Associative Array
Two-dimensional array (runtime)
| #Golfscript | Golfscript | [1 2 3]:a; # numeric only array, assigned to a and then dropped
10,:a; # assign to a [0 1 2 3 4 5 6 7 8 9]
a 0= puts # pick element at index 0 (stack: 0)
a 10+puts # append 10 to the end of a
10 a+puts # prepend 10 to a |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #Tcl | Tcl | package require math::complexnumbers
namespace import math::complexnumbers::*
set a [complex 1 1]
set b [complex 3.14159 1.2]
puts [tostring [+ $a $b]] ;# ==> 4.14159+2.2i
puts [tostring [* $a $b]] ;# ==> 1.94159+4.34159i
puts [tostring [pow $a [complex -1 0]]] ;# ==> 0.5-0.4999999999999999i
puts [tostring [- $a]] ;# ==> -1.0-i |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #PHP | PHP | <?php
echo pow(0,0);
echo 0 ** 0; // PHP 5.6+ only
?> |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #PicoLisp | PicoLisp |
(** 0 0)
|
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #Pike | Pike | write( pow(0, 0) +"\n" ); |
http://rosettacode.org/wiki/Zebra_puzzle | Zebra puzzle | Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses.
The English man lives in the red house.
The Swede has a dog.
The Dane drinks tea.
The green house is immediately to the left of the white house.
They drink coffee in the green house.
The man who smokes Pall Mall has birds.
In the yellow house they smoke Dunhill.
In the middle house they drink milk.
The Norwegian lives in the first house.
The man who smokes Blend lives in the house next to the house with cats.
In a house next to the house where they have a horse, they smoke Dunhill.
The man who smokes Blue Master drinks beer.
The German smokes Prince.
The Norwegian lives next to the blue house.
They drink water in a house next to the house where they smoke Blend.
The question is, who owns the zebra?
Additionally, list the solution for all the houses.
Optionally, show the solution is unique.
Related tasks
Dinesman's multiple-dwelling problem
Twelve statements
| #Elixir | Elixir | defmodule ZebraPuzzle do
defp adjacent?(n,i,g,e) do
Enum.any?(0..3, fn x ->
(Enum.at(n,x)==i and Enum.at(g,x+1)==e) or (Enum.at(n,x+1)==i and Enum.at(g,x)==e)
end)
end
defp leftof?(n,i,g,e) do
Enum.any?(0..3, fn x -> Enum.at(n,x)==i and Enum.at(g,x+1)==e end)
end
defp coincident?(n,i,g,e) do
Enum.with_index(n) |> Enum.any?(fn {x,idx} -> x==i and Enum.at(g,idx)==e end)
end
def solve(content) do
colours = permutation(content[:Colour])
pets = permutation(content[:Pet])
drinks = permutation(content[:Drink])
smokes = permutation(content[:Smoke])
Enum.each(permutation(content[:Nationality]), fn nation ->
if hd(nation) == :Norwegian, do: # 10
Enum.each(colours, fn colour ->
if leftof?(colour, :Green, colour, :White) and # 5
coincident?(nation, :English, colour, :Red) and # 2
adjacent?(nation, :Norwegian, colour, :Blue), do: # 15
Enum.each(pets, fn pet ->
if coincident?(nation, :Swedish, pet, :Dog), do: # 3
Enum.each(drinks, fn drink ->
if Enum.at(drink,2) == :Milk and # 9
coincident?(nation, :Danish, drink, :Tea) and # 4
coincident?(colour, :Green, drink, :Coffee), do: # 6
Enum.each(smokes, fn smoke ->
if coincident?(smoke, :PallMall, pet, :Birds) and # 7
coincident?(smoke, :Dunhill, colour, :Yellow) and # 8
coincident?(smoke, :BlueMaster, drink, :Beer) and # 13
coincident?(smoke, :Prince, nation, :German) and # 14
adjacent?(smoke, :Blend, pet, :Cats) and # 11
adjacent?(smoke, :Blend, drink, :Water) and # 16
adjacent?(smoke, :Dunhill, pet, :Horse), do: # 12
print_out(content, transpose([nation, colour, pet, drink, smoke]))
end)end)end)end)end)
end
defp permutation([]), do: [[]]
defp permutation(list) do
for x <- list, y <- permutation(list -- [x]), do: [x|y]
end
defp transpose(lists) do
List.zip(lists) |> Enum.map(&Tuple.to_list/1)
end
defp print_out(content, result) do
width = for {k,v}<-content, do: Enum.map([k|v], &length(to_char_list &1)) |> Enum.max
fmt = Enum.map_join(width, " ", fn w -> "~-#{w}s" end) <> "~n"
nation = Enum.find(result, fn x -> :Zebra in x end) |> hd
IO.puts "The Zebra is owned by the man who is #{nation}\n"
:io.format fmt, Keyword.keys(content)
:io.format fmt, Enum.map(width, fn w -> String.duplicate("-", w) end)
fmt2 = String.replace(fmt, "s", "w", global: false)
Enum.with_index(result)
|> Enum.each(fn {x,i} -> :io.format fmt2, [i+1 | x] end)
end
end
content = [ House: '',
Nationality: ~w[English Swedish Danish Norwegian German]a,
Colour: ~w[Red Green White Blue Yellow]a,
Pet: ~w[Dog Birds Cats Horse Zebra]a,
Drink: ~w[Tea Coffee Milk Beer Water]a,
Smoke: ~w[PallMall Dunhill BlueMaster Prince Blend]a ]
ZebraPuzzle.solve(content) |
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
| #F.23 | F# |
open System.IO
open System.Xml.XPath
let xml = new StringReader("""
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
""")
let nav = XPathDocument(xml).CreateNavigator()
// first "item"; throws if none exists
let item = nav.SelectSingleNode(@"//item[1]")
// apply a operation (print text value) to all price elements
for price in nav.Select(@"//price") do
printfn "%s" (price.ToString())
// array of all name elements
let names = seq { for name in nav.Select(@"//name") do yield name } |> Seq.toArray |
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #F.C5.8Drmul.C3.A6 | Fōrmulæ | : circle ( x y r h -- f )
rot - dup *
rot dup * +
swap dup * swap
< invert
;
: pixel ( r x y -- r c )
2dup 4 pick 6 / 5 pick 2 / negate circle if 2drop '#' exit then
2dup 4 pick 6 / 5 pick 2 / circle if 2drop '.' exit then
2dup 4 pick 2 / 5 pick 2 / negate circle if 2drop '.' exit then
2dup 4 pick 2 / 5 pick 2 / circle if 2drop '#' exit then
2dup 4 pick 0 circle if
drop 0< if '.' exit else '#' exit then
then
2drop bl
;
: yinyang ( r -- )
dup dup 1+ swap -1 * do
cr
dup dup 2 * 1+ swap -2 * do
I 2 / J pixel emit
loop
loop drop
; |
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #Forth | Forth | : circle ( x y r h -- f )
rot - dup *
rot dup * +
swap dup * swap
< invert
;
: pixel ( r x y -- r c )
2dup 4 pick 6 / 5 pick 2 / negate circle if 2drop '#' exit then
2dup 4 pick 6 / 5 pick 2 / circle if 2drop '.' exit then
2dup 4 pick 2 / 5 pick 2 / negate circle if 2drop '.' exit then
2dup 4 pick 2 / 5 pick 2 / circle if 2drop '#' exit then
2dup 4 pick 0 circle if
drop 0< if '.' exit else '#' exit then
then
2drop bl
;
: yinyang ( r -- )
dup dup 1+ swap -1 * do
cr
dup dup 2 * 1+ swap -2 * do
I 2 / J pixel emit
loop
loop drop
; |
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's state is used in the body of the function.
The Y combinator is itself a stateless function that, when applied to another stateless function, returns a recursive version of the function.
The Y combinator is the simplest of the class of such functions, called fixed-point combinators.
Task
Define the stateless Y combinator and use it to compute factorials and Fibonacci numbers from other stateless functions or lambda expressions.
Cf
Jim Weirich: Adventures in Functional Programming
| #Crystal | Crystal | require "big"
struct RecursiveFunc(T) # a generic recursive function wrapper...
getter recfnc : RecursiveFunc(T) -> T
def initialize(@recfnc) end
end
struct YCombo(T) # a struct or class needs to be used so as to be generic...
def initialize (@fnc : Proc(T) -> T) end
def fixy
g = -> (x : RecursiveFunc(T)) {
@fnc.call(-> { x.recfnc.call(x) }) }
g.call(RecursiveFunc(T).new(g))
end
end
def fac(x) # horrendouly inefficient not using tail calls...
facp = -> (fn : Proc(BigInt -> BigInt)) {
-> (n : BigInt) { n < 2 ? n : n * fn.call.call(n - 1) } }
YCombo.new(facp).fixy.call(BigInt.new(x))
end
def fib(x) # horrendouly inefficient not using tail calls...
facp = -> (fn : Proc(BigInt -> BigInt)) {
-> (n : BigInt) {
n < 3 ? n - 1 : fn.call.call(n - 2) + fn.call.call(n - 1) } }
YCombo.new(facp).fixy.call(BigInt.new(x))
end
puts fac(10)
puts fib(11) # starts from 0 not 1! |
http://rosettacode.org/wiki/Zig-zag_matrix | Zig-zag matrix | Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to encode images).
For example, given 5, produce this array:
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24
Related tasks
Spiral matrix
Identity matrix
Ulam spiral (for primes)
See also
Wiktionary entry: anti-diagonals
| #Crystal | Crystal | def zigzag(n)
(seq=(0...n).to_a).product(seq)
.sort_by {|x,y| [x+y, (x+y).even? ? y : -y]}
.map_with_index{|v, i| {v, i}}.sort.map(&.last).each_slice(n).to_a
end
def print_matrix(m)
format = "%#{m.flatten.max.to_s.size}d " * m[0].size
m.each {|row| puts format % row}
end
print_matrix zigzag(5) |
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #Tcl | Tcl | proc gcd {a b} {
while {$b} {
lassign [list $b [expr {$a % $b}]] a b
}
return $a
}
proc gen_yellowstones {{maxN 30}} {
set r {}
for {set n 1} {$n <= $maxN} {incr n} {
if {$n <= 3} {
lappend r $n
} else {
## NB: list indices start at 0, not 1.
set pred [lindex $r end ] ;# a(n-1): coprime
set prepred [lindex $r end-1] ;# a(n-2): not coprime
for {set k 4} {1} {incr k} {
if {[lsearch -exact $r $k] >= 0} { continue }
if {1 != [gcd $k $pred ]} { continue }
if {1 == [gcd $k $prepred]} { continue }
## candidate k survived all tests...
break
}
lappend r $k
}
}
return $r
}
puts "The first 30 Yellowstone numbers are:"
puts [gen_yellowstones] |
http://rosettacode.org/wiki/Yahoo!_search_interface | Yahoo! search interface | Create a class for searching Yahoo! results.
It must implement a Next Page method, and read URL, Title and Content from results.
| #Run_BASIC | Run BASIC | '--------------------------------------------------------------------------
' send this from the server to the clients browser
'--------------------------------------------------------------------------
html "<table border=1 cellpadding=0 cellspacing=0 bgcolor=wheat>"
html "<tr><td align=center colspan=2>Yahoo Search</td></tr>"
html "<tr><td align=right>Find</td><td>"
textbox #find,findThis$,30
html "</td></tr><tr><td align=right>Page</td><td>"
textbox #page,findPage$,2
html "</td></tr><tr><td align=center colspan=2>"
button #s, "Search", [search]
html " "
button #ex, "Exit", [exit]
html "</td><td></td></tr></table>"
wait
'--------------------------------------------------------------------------
' get search stuff from the clients browser
'--------------------------------------------------------------------------
[search]
findThis$ = trim$(#find contents$())
findPage$ = trim$(#page contents$())
findPage = max(val(findPage$),1) ' must be at least 1
'--------------------------------------------------------------------------
' sho page but keep user interface at the top by not clearing the page (cls)
' so they can change the search or page
' -------------------------------------------------------------------------
url$ = "http://search.yahoo.com/search?p=";findThis$;"&b=";((findPage - 1) * 10) + 1
html httpget$(url$)
wait
[exit]
cls ' clear browser screen and get outta here
wait |
http://rosettacode.org/wiki/Yahoo!_search_interface | Yahoo! search interface | Create a class for searching Yahoo! results.
It must implement a Next Page method, and read URL, Title and Content from results.
| #Tcl | Tcl | package require http
proc fix s {
string map {<b>...</b> "" <b> "" </b> "" <wbr> "" "<wbr />" ""} \
[regsub "</a></h3></div>.*" $s ""]
}
proc YahooSearch {term {page 1}} {
# Build the (ugly) scraper URL
append re {<a class="yschttl spt" href=".+?" >(.+?)</a></h3>}
append re {</div><div class="abstr">(.+?)}
append re {</div><span class=url>(.+?)</span>}
# Perform the query; note that this handles special characters
# in the query term correctly
set q [http::formatQuery p $term b [expr {$page*10-9}]]
set token [http::geturl http://search.yahoo.com/search?$q]
set data [http::data $token]
http::cleanup $token
# Assemble the results into a nice list
set results {}
foreach {- title content url} [regexp -all -inline $re $data] {
lappend results [fix $title] [fix $content] [fix $url]
}
# set up the call for the next page
interp alias {} Nextpage {} YahooSearch $term [incr page]
return $results
}
# Usage: get the first two pages of results
foreach {title content url} [YahooSearch "test"] {
puts $title
}
foreach {title content url} [Nextpage] {
puts $title
} |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #NewLisp | NewLisp |
;;; No built-in big integer exponentiation
(define (exp-big x n)
(setq x (bigint x))
(let (y 1L)
(if (= n 0)
1L
(while (> n 1)
(if (odd? n)
(setq y (* x y)))
(setq x (* x x) n (/ n 2)))
(* x y))))
;
;;; task
(define (test)
(local (res)
; drop the "L" at the end
(setq res (0 (- (length res) 1) (string (exp-big 5 (exp-big 4 (exp-big 3 2))))))
(println "The result has: " (length res) " digits")
(println "First 20 digits: " (0 20 res))
(println "Last 20 digits: " (-20 20 res))))
|
http://rosettacode.org/wiki/Zeckendorf_number_representation | Zeckendorf number representation | Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series.
Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, 5, 8, 13.
The decimal number eleven can be written as 0*13 + 1*8 + 0*5 + 1*3 + 0*2 + 0*1 or 010100 in positional notation where the columns represent multiplication by a particular member of the sequence. Leading zeroes are dropped so that 11 decimal becomes 10100.
10100 is not the only way to make 11 from the Fibonacci numbers however; 0*13 + 1*8 + 0*5 + 0*3 + 1*2 + 1*1 or 010011 would also represent decimal 11. For a true Zeckendorf number there is the added restriction that no two consecutive Fibonacci numbers can be used which leads to the former unique solution.
Task
Generate and show here a table of the Zeckendorf number representations of the decimal numbers zero to twenty, in order.
The intention in this task to find the Zeckendorf form of an arbitrary integer. The Zeckendorf form can be iterated by some bit twiddling rather than calculating each value separately but leave that to another separate task.
Also see
OEIS A014417 for the the sequence of required results.
Brown's Criterion - Numberphile
Related task
Fibonacci sequence
| #Phix | Phix | function zeckendorf(integer n)
integer r = 0, c
sequence fib = {1,1}
while fib[$]<n do
fib &= fib[$] + fib[$-1]
end while
for i=length(fib) to 2 by -1 do
c = n>=fib[i]
r += r+c
n -= c*fib[i]
end for
return r
end function
for i=0 to 20 do
printf(1,"%2d: %7b\n",{i,zeckendorf(i)})
end for
|
http://rosettacode.org/wiki/100_doors | 100 doors | There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6, ...), and toggle it.
The third time, visit every 3rd door (door #3, #6, #9, ...), etc, until you only visit the 100th door.
Task
Answer the question: what state are the doors in after the last pass? Which are open, which are closed?
Alternate:
As noted in this page's discussion page, the only doors that remain open are those whose numbers are perfect squares.
Opening only those doors is an optimization that may also be expressed;
however, as should be obvious, this defeats the intent of comparing implementations across programming languages.
| #Coq | Coq | Require Import List.
Fixpoint rep {A} (a : A) n :=
match n with
| O => nil
| S n' => a::(rep a n')
end.
Fixpoint flip (l : list bool) (n k : nat) : list bool :=
match l with
| nil => nil
| cons h t => match k with
| O => (negb h) :: (flip t n n)
| S k' => h :: (flip t n k')
end
end.
Definition flipeach l n := flip l n n.
Fixpoint flipwhile l n :=
match n with
| O => flipeach l 0
| S n' => flipwhile (flipeach l (S n')) n'
end.
Definition prison cells := flipwhile (rep false cells) cells. |
http://rosettacode.org/wiki/Arrays | Arrays | This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retrieve an element (if available, show both fixed-length arrays and
dynamic arrays, pushing a value into it).
Please discuss at Village Pump: Arrays.
Please merge code in from these obsolete tasks:
Creating an Array
Assigning Values to an Array
Retrieving an Element of an Array
Related tasks
Collections
Creating an Associative Array
Two-dimensional array (runtime)
| #Groovy | Groovy | def aa = [ 1, 25, 31, -3 ] // list
def a = [0] * 100 // list of 100 zeroes
def b = 1..9 // range notation
def c = (1..10).collect { 2.0**it } // each output element is 2**(corresponding invoking list element)
// There are no true "multi-dimensional" arrays in Groovy (as in most C-derived languages).
// Use lists of lists in natural ("row major") order as a stand in.
def d = (0..1).collect { i -> (1..5).collect { j -> 2**(5*i+j) as double } }
def e = [ [ 1.0, 2.0, 3.0, 4.0 ],
[ 5.0, 6.0, 7.0, 8.0 ],
[ 9.0, 10.0, 11.0, 12.0 ],
[ 13.0, 14.0, 15.0, 16.0 ] ]
println aa
println b
println c
println()
d.each { print "["; it.each { elt -> printf "%7.1f ", elt }; println "]" }
println()
e.each { print "["; it.each { elt -> printf "%7.1f ", elt }; println "]" } |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #TI-83_BASIC | TI-83 BASIC | ■ √(–1)
■ ^2 —1
■ + 1 1 +
■ (1+) * 2 2 + 2*
■ (1+) (2) —2 + 2*
■ —(1+) —1 -
■ 1/(2) —1 -
■ real(1 + 2) 1
■ imag(1 + 2) 2 |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #TI-89_BASIC | TI-89 BASIC | ■ √(–1)
■ ^2 —1
■ + 1 1 +
■ (1+) * 2 2 + 2*
■ (1+) (2) —2 + 2*
■ —(1+) —1 -
■ 1/(2) —1 -
■ real(1 + 2) 1
■ imag(1 + 2) 2 |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #PL.2FI | PL/I | zhz: Proc Options(Main);
Dcl a dec float(10) Init(1);
Dcl b dec float(10) Init(0);
Put skip list('1**0=',a**b);
Put skip list('0**1=',b**a);
Put skip list('0**0=',b**b);
End; |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #Plain_English | Plain English | To run:
Start up.
Put 0 into a number.
Raise the number to 0.
Convert the number to a string.
Write the string to the console.
Wait for the escape key.
Shut down. |
http://rosettacode.org/wiki/Zebra_puzzle | Zebra puzzle | Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses.
The English man lives in the red house.
The Swede has a dog.
The Dane drinks tea.
The green house is immediately to the left of the white house.
They drink coffee in the green house.
The man who smokes Pall Mall has birds.
In the yellow house they smoke Dunhill.
In the middle house they drink milk.
The Norwegian lives in the first house.
The man who smokes Blend lives in the house next to the house with cats.
In a house next to the house where they have a horse, they smoke Dunhill.
The man who smokes Blue Master drinks beer.
The German smokes Prince.
The Norwegian lives next to the blue house.
They drink water in a house next to the house where they smoke Blend.
The question is, who owns the zebra?
Additionally, list the solution for all the houses.
Optionally, show the solution is unique.
Related tasks
Dinesman's multiple-dwelling problem
Twelve statements
| #Erlang | Erlang |
-module( zebra_puzzle ).
-export( [task/0] ).
-record( house, {colour, drink, nationality, number, pet, smoke} ).
-record( sorted_houses, {house_1s=[], house_2s=[], house_3s=[], house_4s=[], house_5s=[]} ).
task() ->
Houses = [#house{colour=C, drink=D, nationality=N, number=Nr, pet=P, smoke=S} || C <- all_colours(), D <- all_drinks(), N <- all_nationalities(), Nr <- all_numbers(), P <- all_pets(), S <- all_smokes(), is_all_single_house_rules_ok(C, D, N, Nr, P, S)],
Sorted_houses = lists:foldl( fun house_number_sort/2, #sorted_houses{}, Houses ),
Streets = [[H1, H2, H3, H4, H5] || H1 <- Sorted_houses#sorted_houses.house_1s, H2 <- Sorted_houses#sorted_houses.house_2s, H3 <- Sorted_houses#sorted_houses.house_3s, H4 <- Sorted_houses#sorted_houses.house_4s, H5 <- Sorted_houses#sorted_houses.house_5s, is_all_multi_house_rules_ok(H1, H2, H3, H4, H5)],
[Nationality] = [N || #house{nationality=N, pet=zebra} <- lists:flatten(Streets)],
io:fwrite( "~p owns the zebra~n", [Nationality] ),
io:fwrite( "All solutions ~p~n", [Streets] ),
io:fwrite( "Number of solutions ~p~n", [erlang:length(Streets)] ).
all_colours() -> [blue, green, red, white, yellow].
all_drinks() -> [beer, coffe, milk, tea, water].
all_nationalities() -> [danish, english, german, norveigan, swedish].
all_numbers() -> [1, 2, 3, 4, 5].
all_pets() -> [birds, cats, dog, horse, zebra].
all_smokes() -> [blend, 'blue master', dunhill, 'pall mall', prince].
house_number_sort( #house{number=1}=House, #sorted_houses{house_1s=Houses_1s}=Sorted_houses ) -> Sorted_houses#sorted_houses{house_1s=[House | Houses_1s]};
house_number_sort( #house{number=2}=House, #sorted_houses{house_2s=Houses_2s}=Sorted_houses ) -> Sorted_houses#sorted_houses{house_2s=[House | Houses_2s]};
house_number_sort( #house{number=3}=House, #sorted_houses{house_3s=Houses_3s}=Sorted_houses ) -> Sorted_houses#sorted_houses{house_3s=[House | Houses_3s]};
house_number_sort( #house{number=4}=House, #sorted_houses{house_4s=Houses_4s}=Sorted_houses ) -> Sorted_houses#sorted_houses{house_4s=[House | Houses_4s]};
house_number_sort( #house{number=5}=House, #sorted_houses{house_5s=Houses_5s}=Sorted_houses ) -> Sorted_houses#sorted_houses{house_5s=[House | Houses_5s]}.
is_all_different( [_H] ) -> true;
is_all_different( [H | T] ) -> not lists:member( H, T ) andalso is_all_different( T ).
is_all_multi_house_rules_ok( House1, House2, House3, House4, House5 ) ->
is_rule_1_ok( House1, House2, House3, House4, House5 )
andalso is_rule_5_ok( House1, House2, House3, House4, House5 )
andalso is_rule_11_ok( House1, House2, House3, House4, House5 )
andalso is_rule_12_ok( House1, House2, House3, House4, House5 )
andalso is_rule_15_ok( House1, House2, House3, House4, House5 )
andalso is_rule_16_ok( House1, House2, House3, House4, House5 ).
is_all_single_house_rules_ok( Colour, Drink, Nationality, Number, Pet, Smoke ) ->
is_rule_ok( {rule_number, 2}, {Nationality, english}, {Colour, red})
andalso is_rule_ok( {rule_number, 3}, {Nationality, swedish}, {Pet, dog})
andalso is_rule_ok( {rule_number, 4}, {Nationality, danish}, {Drink, tea})
andalso is_rule_ok( {rule_number, 6}, {Drink, coffe}, {Colour, green})
andalso is_rule_ok( {rule_number, 7}, {Smoke, 'pall mall'}, {Pet, birds})
andalso is_rule_ok( {rule_number, 8}, {Colour, yellow}, {Smoke, dunhill})
andalso is_rule_ok( {rule_number, 9}, {Number, 3}, {Drink, milk})
andalso is_rule_ok( {rule_number, 10}, {Nationality, norveigan}, {Number, 1})
andalso is_rule_ok( {rule_number, 13}, {Smoke, 'blue master'}, {Drink, beer})
andalso is_rule_ok( {rule_number, 14}, {Nationality, german}, {Smoke, prince}).
is_rule_ok( _Rule_number, {A, A}, {B, B} ) -> true;
is_rule_ok( _Rule_number, _A, {B, B} ) -> false;
is_rule_ok( _Rule_number, {A, A}, _B ) -> false;
is_rule_ok( _Rule_number, _A, _B ) -> true.
is_rule_1_ok( #house{number=1}=H1, #house{number=2}=H2, #house{number=3}=H3, #house{number=4}=H4, #house{number=5}=H5 ) ->
is_all_different( [H1#house.colour, H2#house.colour, H3#house.colour, H4#house.colour, H5#house.colour] )
andalso is_all_different( [H1#house.drink, H2#house.drink, H3#house.drink, H4#house.drink, H5#house.drink] )
andalso is_all_different( [H1#house.nationality, H2#house.nationality, H3#house.nationality, H4#house.nationality, H5#house.nationality] )
andalso is_all_different( [H1#house.pet, H2#house.pet, H3#house.pet, H4#house.pet, H5#house.pet] )
andalso is_all_different( [H1#house.smoke, H2#house.smoke, H3#house.smoke, H4#house.smoke, H5#house.smoke] );
is_rule_1_ok( _House1, _House2, _House3, _House4, _House5 ) -> false.
is_rule_5_ok( #house{colour=green}, #house{colour=white}, _House3, _House4, _House5 ) -> true;
is_rule_5_ok( _House1, #house{colour=green}, #house{colour=white}, _House4, _House5 ) -> true;
is_rule_5_ok( _House1, _House2, #house{colour=green}, #house{colour=white}, _House5 ) -> true;
is_rule_5_ok( _House1, _House2, _House3, #house{colour=green}, #house{colour=white} ) -> true;
is_rule_5_ok( _House1, _House2, _House3, _House4, _House5 ) -> false.
is_rule_11_ok( #house{smoke=blend}, #house{pet=cats}, _House3, _House4, _House5 ) -> true;
is_rule_11_ok( _House1, #house{smoke=blend}, #house{pet=cats}, _House4, _House5 ) -> true;
is_rule_11_ok( _House1, _House2, #house{smoke=blend}, #house{pet=cats}, _House5 ) -> true;
is_rule_11_ok( _House1, _House2, _House3, #house{smoke=blend}, #house{pet=cats} ) -> true;
is_rule_11_ok( #house{pet=cats}, #house{smoke=blend}, _House3, _House4, _House5 ) -> true;
is_rule_11_ok( _House1, #house{pet=cats}, #house{smoke=blend}, _House4, _House5 ) -> true;
is_rule_11_ok( _House1, _House2, #house{pet=cats}, #house{smoke=blend}, _House5 ) -> true;
is_rule_11_ok( _House1, _House2, _House3, #house{pet=cats}, #house{smoke=blend} ) -> true;
is_rule_11_ok( _House1, _House2, _House3, _House4, _House5 ) -> false.
is_rule_12_ok( #house{smoke=dunhill}, #house{pet=horse}, _House3, _House4, _House5 ) -> true;
is_rule_12_ok( _House1, #house{smoke=dunhill}, #house{pet=horse}, _House4, _House5 ) -> true;
is_rule_12_ok( _House1, _House2, #house{smoke=dunhill}, #house{pet=horse}, _House5 ) -> true;
is_rule_12_ok( _House1, _House2, _House3, #house{smoke=dunhill}, #house{pet=horse} ) -> true;
is_rule_12_ok( #house{pet=horse}, #house{smoke=dunhill}, _House3, _House4, _House5 ) -> true;
is_rule_12_ok( _House1, #house{pet=horse}, #house{smoke=dunhill}, _House4, _House5 ) -> true;
is_rule_12_ok( _House1, _House2, #house{pet=horse}, #house{smoke=dunhill}, _House5 ) -> true;
is_rule_12_ok( _House1, _House2, _House3, #house{pet=horse}, #house{smoke=dunhill} ) -> true;
is_rule_12_ok( _House1, _House2, _House3, _House4, _House5 ) -> false.
is_rule_15_ok( #house{nationality=norveigan}, #house{colour=blue}, _House3, _House4, _House5 ) -> true;
is_rule_15_ok( _House1, #house{nationality=norveigan}, #house{colour=blue}, _House4, _House5 ) -> true;
is_rule_15_ok( _House1, _House2, #house{nationality=norveigan}, #house{colour=blue}, _House5 ) -> true;
is_rule_15_ok( _House1, _House2, _House3, #house{nationality=norveigan}, #house{colour=blue} ) -> true;
is_rule_15_ok( #house{colour=blue}, #house{nationality=norveigan}, _House3, _House4, _House5 ) -> true;
is_rule_15_ok( _House1, #house{colour=blue}, #house{nationality=norveigan}, _House4, _House5 ) -> true;
is_rule_15_ok( _House1, _House2, #house{drink=water}, #house{nationality=norveigan}, _House5 ) -> true;
is_rule_15_ok( _House1, _House2, _House3, #house{drink=water}, #house{nationality=norveigan} ) -> true;
is_rule_15_ok( _House1, _House2, _House3, _House4, _House5 ) -> false.
is_rule_16_ok( #house{smoke=blend}, #house{drink=water}, _House3, _House4, _House5 ) -> true;
is_rule_16_ok( _House1, #house{smoke=blend}, #house{drink=water}, _House4, _House5 ) -> true;
is_rule_16_ok( _House1, _House2, #house{smoke=blend}, #house{drink=water}, _House5 ) -> true;
is_rule_16_ok( _House1, _House2, _House3, #house{smoke=blend}, #house{drink=water} ) -> true;
is_rule_16_ok( #house{drink=water}, #house{smoke=blend}, _House3, _House4, _House5 ) -> true;
is_rule_16_ok( _House1, #house{drink=water}, #house{smoke=blend}, _House4, _House5 ) -> true;
is_rule_16_ok( _House1, _House2, #house{drink=water}, #house{smoke=blend}, _House5 ) -> true;
is_rule_16_ok( _House1, _House2, _House3, #house{drink=water}, #house{smoke=blend} ) -> true;
is_rule_16_ok( _House1, _House2, _House3, _House4, _House5 ) -> false.
|
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
| #Factor | Factor |
! Get first item element
"""<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>""" string>xml "item" deep-tag-named
! Print out prices
"""<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>""" string>xml "price" deep-tags-named [ children>> first ] map
! Array of all name elements
"""<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>""" string>xml "name" deep-tags-named
|
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
| #Gastona | Gastona | #javaj#
<frames> oSal, XML Path sample, 300, 400
#data#
<xml>
//<inventory title="OmniCorp Store #45x10^3">
// <section name="health">
// <item upc="123456789" stock="12">
// <name>Invisibility Cream</name>
// <price>14.50</price>
// <description>Makes you invisible</description>
// </item>
// <item upc="445322344" stock="18">
// <name>Levitation Salve</name>
// <price>23.99</price>
// <description>Levitate yourself for up to 3 hours per application</description>
// </item>
// </section>
// <section name="food">
// <item upc="485672034" stock="653">
// <name>Blork and Freen Instameal</name>
// <price>4.95</price>
// <description>A tasty meal in a tablet; just add water</description>
// </item>
// <item upc="132957764" stock="44">
// <name>Grob winglets</name>
// <price>3.56</price>
// <description>Tender winglets of Grob. Just add water</description>
// </item>
// </section>
//</inventory>
<DEEP_SQL_XML>
DEEP DB, SELECT, xmelon_data
,, path pathStr
,, tag tagStr
,, patCnt
,, dataPlace
,, value
#listix#
<main>
//parsing xml data ...
GEN, :mem datos, xml
XMELON, FILE2DB, :mem datos
//
//first item ...
//
//
LOOP, SQL,, //SELECT patCnt AS patITEM1 FROM (@<DEEP_SQL_XML>) WHERE path_pathStr == '/inventory/section/item' LIMIT 1
,HEAD, //<item
,, LOOP, SQL,, //SELECT * FROM (@<DEEP_SQL_XML>) WHERE patCnt == @<patITEM1> AND dataPlace == 'A'
,, , LINK, ""
,, ,, // @<tag_tagStr>="@<value>"
,, //>
,, //
,, LOOP, SQL,, //SELECT * FROM (@<DEEP_SQL_XML>) WHERE patCnt == @<patITEM1> AND dataPlace != 'A'
,, ,, // <@<tag_tagStr>>@<value></@<tag_tagStr>>
,TAIL, //
,TAIL, //</item>
//
//
//report prices ...
//
LOOP, SQL,, //SELECT value FROM (@<DEEP_SQL_XML>) WHERE tag_tagStr == 'price'
, LINK, ", "
,, @<value>
//
//put names into a variable
//
VAR=, tabnames, "name"
LOOP, SQL,, //SELECT value FROM (@<DEEP_SQL_XML>) WHERE tag_tagStr == 'name'
, LINK, ""
,, VAR+, tabnames, @<value>
DUMP, data,, tabnames
|
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #Go | Go | package main
import (
"fmt"
"os"
"text/template"
)
var tmpl = `<?xml version="1.0"?>
<svg xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink"
width="210" height="150">
<symbol id="yy" viewBox="0 0 200 200">
<circle stroke="black" stroke-width="2" fill="white"
cx="100" cy="100" r="99" />
<path fill="black"
d="M100 100 a49 49 0 0 0 0 -98
v-1 a99 99 0 0 1 0 198
v-1 a49 49 0 0 1 0 -98" />
<circle fill="black" cx="100" cy="51" r="17" />
<circle fill="white" cx="100" cy="149" r="17" />
</symbol>
{{range .}}<use xlink:href="#yy"
x="{{.X}}" y="{{.Y}}" width="{{.Sz}}" height="{{.Sz}}"/>
{{end}}</svg>
`
// structure specifies position and size to draw symbol
type xysz struct {
X, Y, Sz int
}
// example data to specify drawing the symbol twice,
// with different position and size.
var yys = []xysz{
{20, 20, 100},
{140, 30, 60},
}
func main() {
xt := template.New("")
template.Must(xt.Parse(tmpl))
f, err := os.Create("yy.svg")
if err != nil {
fmt.Println(err)
return
}
if err := xt.Execute(f, yys); err != nil {
fmt.Println(err)
}
f.Close()
} |
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's state is used in the body of the function.
The Y combinator is itself a stateless function that, when applied to another stateless function, returns a recursive version of the function.
The Y combinator is the simplest of the class of such functions, called fixed-point combinators.
Task
Define the stateless Y combinator and use it to compute factorials and Fibonacci numbers from other stateless functions or lambda expressions.
Cf
Jim Weirich: Adventures in Functional Programming
| #D | D | import std.stdio, std.traits, std.algorithm, std.range;
auto Y(S, T...)(S delegate(T) delegate(S delegate(T)) f) {
static struct F {
S delegate(T) delegate(F) f;
alias f this;
}
return (x => x(x))(F(x => f((T v) => x(x)(v))));
}
void main() { // Demo code:
auto factorial = Y((int delegate(int) self) =>
(int n) => 0 == n ? 1 : n * self(n - 1)
);
auto ackermann = Y((ulong delegate(ulong, ulong) self) =>
(ulong m, ulong n) {
if (m == 0) return n + 1;
if (n == 0) return self(m - 1, 1);
return self(m - 1, self(m, n - 1));
});
writeln("factorial: ", 10.iota.map!factorial);
writeln("ackermann(3, 5): ", ackermann(3, 5));
} |
http://rosettacode.org/wiki/Zig-zag_matrix | Zig-zag matrix | Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to encode images).
For example, given 5, produce this array:
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24
Related tasks
Spiral matrix
Identity matrix
Ulam spiral (for primes)
See also
Wiktionary entry: anti-diagonals
| #D | D | int[][] zigZag(in int n) pure nothrow @safe {
static void move(in int n, ref int i, ref int j)
pure nothrow @safe @nogc {
if (j < n - 1) {
if (i > 0) i--;
j++;
} else
i++;
}
auto a = new int[][](n, n);
int x, y;
foreach (v; 0 .. n ^^ 2) {
a[y][x] = v;
(x + y) % 2 ? move(n, x, y) : move(n, y, x);
}
return a;
}
void main() {
import std.stdio;
writefln("%(%(%2d %)\n%)", 5.zigZag);
} |
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #uBasic.2F4tH | uBasic/4tH | Dim @y(30)
@y(0) = 1
@y(1) = 2
@y(2) = 3
For i = 3 To 29
k = 3
Do
k = k + 1
If (FUNC(_gcd(k, @y(i-2))) = 1) + (FUNC(_gcd(k, @y(i-1))) > 1) Then
Continue
EndIf
For j = 0 To i - 1
If @y(j) = k Then Unloop : Continue
Next
@y(i) = k : Break
Loop
Next
For i = 0 To 29
Print @y(i); " ";
Next
Print : End
_gcd Param (2)
If b@ = 0 Then Return (a@)
Return (FUNC(_gcd(b@, a@ % b@))) |
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #VBA | VBA |
Function gcd(a As Long, b As Long) As Long
If b = 0 Then
gcd = a
Exit Function
End If
gcd = gcd(b, a Mod b)
End Function
Sub Yellowstone()
Dim i As Long, j As Long, k As Long, Y(1 To 30) As Long
Y(1) = 1
Y(2) = 2
Y(3) = 3
For i = 4 To 30
k = 3
Do
k = k + 1
If gcd(k, Y(i - 2)) = 1 Or gcd(k, Y(i - 1)) > 1 Then GoTo EndLoop:
For j = 1 To i - 1
If Y(j) = k Then GoTo EndLoop:
Next j
Y(i) = k
Exit Do
EndLoop:
Loop
Next i
For i = 1 To 30
Debug.Print Y(i) & " ";
Next i
End Sub
|
http://rosettacode.org/wiki/Yahoo!_search_interface | Yahoo! search interface | Create a class for searching Yahoo! results.
It must implement a Next Page method, and read URL, Title and Content from results.
| #TXR | TXR | #!/usr/bin/txr -f
@(next :args)
@(cases)
@ QUERY
@ PAGE
@(or)
@ (throw error "specify query and page# (from zero)")
@(end)
@(next (open-command "!wget -O - http://search.yahoo.com/search?p=@QUERY\&b=@{PAGE}1 2> /dev/null"))
@(all)
@ (coll)<a class="yschttl spt" href="@URL" @/[^>]+/>@TITLE</a>@(end)
@(and)
@ (coll)<div class="@/abstr|sm-abs/">@ABSTR</div>@(end)
@(end)
@(output)
@ (repeat)
TITLE: @TITLE
URL: @URL
TEXT: @ABSTR
---
@ (end)
@(end)
|
http://rosettacode.org/wiki/Yahoo!_search_interface | Yahoo! search interface | Create a class for searching Yahoo! results.
It must implement a Next Page method, and read URL, Title and Content from results.
| #Wren | Wren | /* yahoo_search_interface.wren */
import "./pattern" for Pattern
class YahooSearch {
construct new(url, title, desc) {
_url = url
_title = title
_desc = desc
}
toString { "URL: %(_url)\nTitle: %(_title)\nDescription: %(_desc)\n" }
}
var CURLOPT_URL = 10002
var CURLOPT_FOLLOWLOCATION = 52
var CURLOPT_WRITEFUNCTION = 20011
var CURLOPT_WRITEDATA = 10001
foreign class Buffer {
construct new() {} // C will allocate buffer of a suitable size
foreign value // returns buffer contents as a string
}
foreign class Curl {
construct easyInit() {}
foreign easySetOpt(opt, param)
foreign easyPerform()
foreign easyCleanup()
}
var curl = Curl.easyInit()
var getContent = Fn.new { |url|
var buffer = Buffer.new()
curl.easySetOpt(CURLOPT_URL, url)
curl.easySetOpt(CURLOPT_FOLLOWLOCATION, 1)
curl.easySetOpt(CURLOPT_WRITEFUNCTION, 0) // write function to be supplied by C
curl.easySetOpt(CURLOPT_WRITEDATA, buffer)
curl.easyPerform()
return buffer.value
}
var p1 = Pattern.new("class/=\" d-ib ls-05 fz-20 lh-26 td-hu tc va-bot mxw-100p\" href/=\"[+1^\"]\"")
var p2 = Pattern.new("class/=\" d-ib p-abs t-0 l-0 fz-14 lh-20 fc-obsidian wr-bw ls-n pb-4\">[+1^<]<")
var p3 = Pattern.new("<span class/=\" fc-falcon\">[+1^<]<")
var pageSize = 7
var totalCount = 0
var yahooSearch = Fn.new { |query, page|
System.print("Page %(page):\n=======\n")
var next = (page - 1) * pageSize + 1
var url = "https://search.yahoo.com/search?fr=opensearch&pz=%(pageSize)&p=%(query)&b=%(next)"
var content = getContent.call(url).replace("<b>", "").replace("</b>", "")
var matches1 = p1.findAll(content)
var count = matches1.count
if (count == 0) return false
var matches2 = p2.findAll(content)
var matches3 = p3.findAll(content)
totalCount = totalCount + count
var ys = List.filled(count, null)
for (i in 0...count) {
var url = matches1[i].capsText[0]
var title = matches2[i].capsText[0]
var desc = matches3[i].capsText[0].replace("'", "'")
ys[i] = YahooSearch.new(url, title, desc)
}
System.print(ys.join("\n"))
return true
}
var page = 1
var limit = 2
var query = "rosettacode"
System.print("Searching for '%(query)' on Yahoo!\n")
while (page <= limit && yahooSearch.call(query, page)) {
page = page + 1
System.print()
}
System.print("Displayed %(limit) pages with a total of %(totalCount) entries.")
curl.easyCleanup() |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref savelog symbols
import java.math.BigInteger
numeric digits 30 -- needed to report the run-time
nanoFactor = 10 ** 9
t1 = System.nanoTime
x = BigInteger.valueOf(5)
x = x.pow(BigInteger.valueOf(4).pow(BigInteger.valueOf(3).pow(2).intValue()).intValue())
n = Rexx(x.toString)
t2 = System.nanoTime
td = t2 - t1
say "Run time in seconds:" td / nanoFactor
say
check = "62060698786608744707...92256259918212890625"
sample = n.left(20)"..."n.right(20)
say "Expected result:" check
say " Actual result:" sample
say " digits:" n.length
say
if check = sample
then
say "Result confirmed"
else
say "Result does not satisfy test"
return |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #Nim | Nim | import bigints
var x = 5.pow 4.pow 3.pow 2
var s = $x
echo s[0..19]
echo s[s.high - 19 .. s.high]
echo s.len |
http://rosettacode.org/wiki/Zeckendorf_number_representation | Zeckendorf number representation | Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series.
Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, 5, 8, 13.
The decimal number eleven can be written as 0*13 + 1*8 + 0*5 + 1*3 + 0*2 + 0*1 or 010100 in positional notation where the columns represent multiplication by a particular member of the sequence. Leading zeroes are dropped so that 11 decimal becomes 10100.
10100 is not the only way to make 11 from the Fibonacci numbers however; 0*13 + 1*8 + 0*5 + 0*3 + 1*2 + 1*1 or 010011 would also represent decimal 11. For a true Zeckendorf number there is the added restriction that no two consecutive Fibonacci numbers can be used which leads to the former unique solution.
Task
Generate and show here a table of the Zeckendorf number representations of the decimal numbers zero to twenty, in order.
The intention in this task to find the Zeckendorf form of an arbitrary integer. The Zeckendorf form can be iterated by some bit twiddling rather than calculating each value separately but leave that to another separate task.
Also see
OEIS A014417 for the the sequence of required results.
Brown's Criterion - Numberphile
Related task
Fibonacci sequence
| #Phixmonti | Phixmonti | def Zeckendorf /# n -- #/
0 var i 0 var c 1 1 2 tolist var pattern
true
while
i 8 int>bit reverse
pattern find
not if
c print ":\t" print print nl
dup c == if
false
else
c 1 + var c
true
endif
endif
i 1 + var i
endwhile
drop
enddef
20 Zeckendorf |
http://rosettacode.org/wiki/Zeckendorf_number_representation | Zeckendorf number representation | Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series.
Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, 5, 8, 13.
The decimal number eleven can be written as 0*13 + 1*8 + 0*5 + 1*3 + 0*2 + 0*1 or 010100 in positional notation where the columns represent multiplication by a particular member of the sequence. Leading zeroes are dropped so that 11 decimal becomes 10100.
10100 is not the only way to make 11 from the Fibonacci numbers however; 0*13 + 1*8 + 0*5 + 0*3 + 1*2 + 1*1 or 010011 would also represent decimal 11. For a true Zeckendorf number there is the added restriction that no two consecutive Fibonacci numbers can be used which leads to the former unique solution.
Task
Generate and show here a table of the Zeckendorf number representations of the decimal numbers zero to twenty, in order.
The intention in this task to find the Zeckendorf form of an arbitrary integer. The Zeckendorf form can be iterated by some bit twiddling rather than calculating each value separately but leave that to another separate task.
Also see
OEIS A014417 for the the sequence of required results.
Brown's Criterion - Numberphile
Related task
Fibonacci sequence
| #PHP | PHP |
<?php
$m = 20;
$F = array(1,1);
while ($F[count($F)-1] <= $m)
$F[] = $F[count($F)-1] + $F[count($F)-2];
while ($n = $m--) {
while ($F[count($F)-1] > $n) array_pop($F);
$l = count($F)-1;
print "$n: ";
while ($n) {
if ($n >= $F[$l]) {
$n = $n - $F[$l];
print '1';
} else print '0';
--$l;
}
print str_repeat('0',$l);
print "\n";
}
?>
|
http://rosettacode.org/wiki/100_doors | 100 doors | There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6, ...), and toggle it.
The third time, visit every 3rd door (door #3, #6, #9, ...), etc, until you only visit the 100th door.
Task
Answer the question: what state are the doors in after the last pass? Which are open, which are closed?
Alternate:
As noted in this page's discussion page, the only doors that remain open are those whose numbers are perfect squares.
Opening only those doors is an optimization that may also be expressed;
however, as should be obvious, this defeats the intent of comparing implementations across programming languages.
| #Cowgol | Cowgol | include "cowgol.coh";
var doors: uint8[101]; # one extra so we can start at 1
var pass: @indexof doors;
var door: @indexof doors;
MemZero(&doors as [uint8], @bytesof doors);
pass := 1;
while pass <= 100 loop
door := pass;
while door <= 100 loop
doors[door] := 1-doors[door];
door := door + pass;
end loop;
pass := pass + 1;
end loop;
door := 1;
while door <= 100 loop
if doors[door] == 1 then
print_i8(door);
print(" is open\n");
end if;
door := door + 1;
end loop; |
http://rosettacode.org/wiki/Arrays | Arrays | This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retrieve an element (if available, show both fixed-length arrays and
dynamic arrays, pushing a value into it).
Please discuss at Village Pump: Arrays.
Please merge code in from these obsolete tasks:
Creating an Array
Assigning Values to an Array
Retrieving an Element of an Array
Related tasks
Collections
Creating an Associative Array
Two-dimensional array (runtime)
| #GUISS | GUISS | Start,Programs,Lotus 123,Type:Bob[downarrow],Kat[downarrow],Sarah[downarrow] |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #UNIX_Shell | UNIX Shell | typeset -T Complex_t=(
float real=0
float imag=0
function to_s {
print -- "${_.real} + ${_.imag} i"
}
function dup {
nameref other=$1
_=( real=${other.real} imag=${other.imag} )
}
function add {
typeset varname
for varname; do
nameref other=$varname
(( _.real += other.real ))
(( _.imag += other.imag ))
done
}
function negate {
(( _.real *= -1 ))
(( _.imag *= -1 ))
}
function conjugate {
(( _.imag *= -1 ))
}
function multiply {
typeset varname
for varname; do
nameref other=$varname
float a=${_.real} b=${_.imag} c=${other.real} d=${other.imag}
(( _.real = a*c - b*d ))
(( _.imag = b*c + a*d ))
done
}
function inverse {
if (( _.real == 0 && _.imag == 0 )); then
print -u2 "division by zero"
return 1
fi
float denom=$(( _.real*_.real + _.imag*_.imag ))
(( _.real = _.real / denom ))
(( _.imag = -1 * _.imag / denom ))
}
)
Complex_t a=(real=1 imag=1)
a.to_s # 1 + 1 i
Complex_t b=(real=3.14159 imag=1.2)
b.to_s # 3.14159 + 1.2 i
Complex_t c
c.add a b
c.to_s # 4.14159 + 2.2 i
c.negate
c.to_s # -4.14159 + -2.2 i
c.conjugate
c.to_s # -4.14159 + 2.2 i
c.dup a
c.multiply b
c.to_s # 1.94159 + 4.34159 i
Complex_t d=(real=2 imag=1)
d.inverse
d.to_s # 0.4 + -0.2 i |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #PowerShell | PowerShell | Write-Host "0 ^ 0 = " ([math]::pow(0,0)) |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #PureBasic | PureBasic |
If OpenConsole()
PrintN("Zero to the zero power is " + Pow(0,0))
PrintN("")
PrintN("Press any key to close the console")
Repeat: Delay(10) : Until Inkey() <> ""
CloseConsole()
EndIf
|
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #Pyret | Pyret | num-expt(0, 0) |
http://rosettacode.org/wiki/Zebra_puzzle | Zebra puzzle | Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses.
The English man lives in the red house.
The Swede has a dog.
The Dane drinks tea.
The green house is immediately to the left of the white house.
They drink coffee in the green house.
The man who smokes Pall Mall has birds.
In the yellow house they smoke Dunhill.
In the middle house they drink milk.
The Norwegian lives in the first house.
The man who smokes Blend lives in the house next to the house with cats.
In a house next to the house where they have a horse, they smoke Dunhill.
The man who smokes Blue Master drinks beer.
The German smokes Prince.
The Norwegian lives next to the blue house.
They drink water in a house next to the house where they smoke Blend.
The question is, who owns the zebra?
Additionally, list the solution for all the houses.
Optionally, show the solution is unique.
Related tasks
Dinesman's multiple-dwelling problem
Twelve statements
| #ERRE | ERRE |
PROGRAM ZEBRA_PUZZLE
DIM DRINK$[4],NATION$[4],COLR$[4],SMOKE$[4],ANIMAL$[4]
DIM PERM$[120],X$[4]
PROCEDURE PERMUTATION(X$[]->X$[],OK)
LOCAL I%,J%
FOR I%=UBOUND(X$,1)-1 TO 0 STEP -1 DO
EXIT IF X$[I%]<X$[I%+1]
END FOR
IF I%<0 THEN OK=FALSE EXIT PROCEDURE END IF
J%=UBOUND(X$,1)
WHILE X$[J%]<=X$[I%] DO
J%=J%-1
END WHILE
SWAP(X$[I%],X$[J%])
I%=I%+1
J%=UBOUND(X$,1)
WHILE I%<J% DO
SWAP(X$[I%],X$[J%])
I%=I%+1
J%=J%-1
END WHILE
OK=TRUE
END PROCEDURE
BEGIN
! The names (only used for printing the results)
DATA("Beer","Coffee","Milk","Tea","Water")
DATA("Denmark","England","Germany","Norway","Sweden")
DATA("Blue","Green","Red","White","Yellow")
DATA("Blend","BlueMaster","Dunhill","PallMall","Prince")
DATA("Birds","Cats","Dog","Horse","Zebra")
FOR I%=0 TO 4 DO READ(DRINK$[I%]) END FOR
FOR I%=0 TO 4 DO READ(NATION$[I%]) END FOR
FOR I%=0 TO 4 DO READ(COLR$[I%]) END FOR
FOR I%=0 TO 4 DO READ(SMOKE$[I%]) END FOR
FOR I%=0 TO 4 DO READ(ANIMAL$[I%]) END FOR
! Some single-character tags:
A$="A" B$="B" c$="C" d$="D" e$="E"
! ERRE doesn't have enumerations!
Beer$=A$ Coffee$=B$ Milk$=c$ TeA$=d$ Water$=e$
Denmark$=A$ England$=B$ Germany$=c$ Norway$=d$ Sweden$=e$
Blue$=A$ Green$=B$ Red$=c$ White$=d$ Yellow$=e$
Blend$=A$ BlueMaster$=B$ Dunhill$=c$ PallMall$=d$ Prince$=e$
Birds$=A$ Cats$=B$ Dog$=c$ Horse$=d$ ZebrA$=e$
PRINT(CHR$(12);)
! Create the 120 permutations of 5 objects:
X$[0]=A$ X$[1]=B$ X$[2]=C$ X$[3]=D$ X$[4]=E$
REPEAT
P%=P%+1
PERM$[P%]=X$[0]+X$[1]+X$[2]+X$[3]+X$[4]
PERMUTATION(X$[]->X$[],OK)
UNTIL NOT OK
! Solve:
SOLUTIONS%=0
T1=TIMER
FOR NATION%=1 TO 120 DO
NATION$=PERM$[NATION%]
IF LEFT$(NATION$,1)=Norway$ THEN
FOR COLR%=1 TO 120 DO
COLR$=PERM$[COLR%]
IF INSTR(COLR$,Green$+White$)<>0 AND INSTR(NATION$,England$)=INSTR(COLR$,Red$) AND ABS(INSTR(NATION$,Norway$)-INSTR(COLR$,Blue$))=1 THEN
FOR DRINK%=1 TO 120 DO
DRINK$=PERM$[DRINK%]
IF MID$(DRINK$,3,1)=Milk$ AND INSTR(NATION$,Denmark$)=INSTR(DRINK$,TeA$) AND INSTR(DRINK$,Coffee$)=INSTR(COLR$,Green$) THEN
FOR SmOKe%=1 TO 120 DO
SmOKe$=PERM$[SMOKE%]
IF INSTR(NATION$,Germany$)=INSTR(SmOKe$,Prince$) AND INSTR(SmOKe$,BlueMaster$)=INSTR(DRINK$,Beer$) AND ABS(INSTR(SmOKe$,Blend$)-INSTR(DRINK$,Water$))=1 AND INSTR(SmOKe$,Dunhill$)=INSTR(COLR$,Yellow$) THEN
FOR ANIMAL%=1 TO 120 DO
ANIMAL$=PERM$[ANIMAL%]
IF INSTR(NATION$,Sweden$)=INSTR(ANIMAL$,Dog$) AND INSTR(SmOKe$,PallMall$)=INSTR(ANIMAL$,Birds$) AND ABS(INSTR(SmOKe$,Blend$)-INSTR(ANIMAL$,Cats$))=1 AND ABS(INSTR(SmOKe$,Dunhill$)-INSTR(ANIMAL$,Horse$))=1 THEN
PRINT("House Drink Nation Colour Smoke Animal")
PRINT("---------------------------------------------------------------------------")
FOR house%=1 TO 5 DO
PRINT(house%;)
PRINT(TAB(10);DRINK$[ASC(MID$(DRINK$,house%))-65];)
PRINT(TAB(25);NATION$[ASC(MID$(NATION$,house%))-65];)
PRINT(TAB(40);COLR$[ASC(MID$(COLR$,house%))-65];)
PRINT(TAB(55);SMOKE$[ASC(MID$(SmOKe$,house%))-65];)
PRINT(TAB(70);ANIMAL$[ASC(MID$(ANIMAL$,house%))-65])
END FOR
SOLUTIONS%=SOLUTIONS%+1
END IF
END FOR ! ANIMAL%
END IF
END FOR ! SmOKe%
END IF
END FOR ! DRINK%
END IF
END FOR ! COLR%
END IF
END FOR ! NATION%
PRINT("Number of solutions=";SOLUTIONS%)
PRINT("Solved in ";TIMER-T1;" seconds")
END PROGRAM |
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
| #Go | Go | package main
import (
"encoding/xml"
"fmt"
"log"
"os"
)
type Inventory struct {
XMLName xml.Name `xml:"inventory"`
Title string `xml:"title,attr"`
Sections []struct {
XMLName xml.Name `xml:"section"`
Name string `xml:"name,attr"`
Items []struct {
XMLName xml.Name `xml:"item"`
Name string `xml:"name"`
UPC string `xml:"upc,attr"`
Stock int `xml:"stock,attr"`
Price float64 `xml:"price"`
Description string `xml:"description"`
} `xml:"item"`
} `xml:"section"`
}
// To simplify main's error handling
func printXML(s string, v interface{}) {
fmt.Println(s)
b, err := xml.MarshalIndent(v, "", "\t")
if err != nil {
log.Fatal(err)
}
fmt.Println(string(b))
fmt.Println()
}
func main() {
fmt.Println("Reading XML from standard input...")
var inv Inventory
dec := xml.NewDecoder(os.Stdin)
if err := dec.Decode(&inv); err != nil {
log.Fatal(err)
}
// At this point, inv is Go struct with all the fields filled
// in from the XML data. Well-formed XML input that doesn't
// match the specification of the fields in the Go struct are
// discarded without error.
// We can reformat the parts we parsed:
//printXML("Got:", inv)
// 1. Retrieve first item:
item := inv.Sections[0].Items[0]
fmt.Println("item variable:", item)
printXML("As XML:", item)
// 2. Action on each price:
fmt.Println("Prices:")
var totalValue float64
for _, s := range inv.Sections {
for _, i := range s.Items {
fmt.Println(i.Price)
totalValue += i.Price * float64(i.Stock)
}
}
fmt.Println("Total inventory value:", totalValue)
fmt.Println()
// 3. Slice of all the names:
var names []string
for _, s := range inv.Sections {
for _, i := range s.Items {
names = append(names, i.Name)
}
}
fmt.Printf("names: %q\n", names)
} |
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #Haskell | Haskell | {-# LANGUAGE NoMonomorphismRestriction #-}
import Diagrams.Prelude
import Diagrams.Backend.Cairo.CmdLine
yinyang = lw 0 $
perim # lw 0.003 <>
torus white black # xform id <>
torus black white # xform negate <>
clipBy perim base
where perim = arc 0 (360 :: Deg) # scale (1/2)
torus c c' = circle (1/3) # fc c' <> circle 1 # fc c
xform f = translateY (f (1/4)) . scale (1/4)
base = rect (1/2) 1 # fc white ||| rect (1/2) 1 # fc black
main = defaultMain $
pad 1.1 $
beside (2,-1) yinyang (yinyang # scale (1/4)) |
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's state is used in the body of the function.
The Y combinator is itself a stateless function that, when applied to another stateless function, returns a recursive version of the function.
The Y combinator is the simplest of the class of such functions, called fixed-point combinators.
Task
Define the stateless Y combinator and use it to compute factorials and Fibonacci numbers from other stateless functions or lambda expressions.
Cf
Jim Weirich: Adventures in Functional Programming
| #Delphi | Delphi | program Y;
{$APPTYPE CONSOLE}
uses
SysUtils;
type
YCombinator = class sealed
class function Fix<T> (F: TFunc<TFunc<T, T>, TFunc<T, T>>): TFunc<T, T>; static;
end;
TRecursiveFuncWrapper<T> = record // workaround required because of QC #101272 (http://qc.embarcadero.com/wc/qcmain.aspx?d=101272)
type
TRecursiveFunc = reference to function (R: TRecursiveFuncWrapper<T>): TFunc<T, T>;
var
O: TRecursiveFunc;
end;
class function YCombinator.Fix<T> (F: TFunc<TFunc<T, T>, TFunc<T, T>>): TFunc<T, T>;
var
R: TRecursiveFuncWrapper<T>;
begin
R.O := function (W: TRecursiveFuncWrapper<T>): TFunc<T, T>
begin
Result := F (function (I: T): T
begin
Result := W.O (W) (I);
end);
end;
Result := R.O (R);
end;
type
IntFunc = TFunc<Integer, Integer>;
function AlmostFac (F: IntFunc): IntFunc;
begin
Result := function (N: Integer): Integer
begin
if N <= 1 then
Result := 1
else
Result := N * F (N - 1);
end;
end;
function AlmostFib (F: TFunc<Integer, Integer>): TFunc<Integer, Integer>;
begin
Result := function (N: Integer): Integer
begin
if N <= 2 then
Result := 1
else
Result := F (N - 1) + F (N - 2);
end;
end;
var
Fib, Fac: IntFunc;
begin
Fib := YCombinator.Fix<Integer> (AlmostFib);
Fac := YCombinator.Fix<Integer> (AlmostFac);
Writeln ('Fib(10) = ', Fib (10));
Writeln ('Fac(10) = ', Fac (10));
end. |
http://rosettacode.org/wiki/Zig-zag_matrix | Zig-zag matrix | Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to encode images).
For example, given 5, produce this array:
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24
Related tasks
Spiral matrix
Identity matrix
Ulam spiral (for primes)
See also
Wiktionary entry: anti-diagonals
| #E | E | /** Missing scalar multiplication, but we don't need it. */
def makeVector2(x, y) {
return def vector {
to x() { return x }
to y() { return y }
to add(other) { return makeVector2(x + other.x(), y + other.y()) }
to clockwise() { return makeVector2(-y, x) }
}
}
/** Bugs: (1) The printing is specialized. (2) No bounds check on the column. */
def makeFlex2DArray(rows, cols) {
def storage := ([null] * (rows * cols)).diverge()
return def flex2DArray {
to __printOn(out) {
for y in 0..!rows {
for x in 0..!cols {
out.print(<import:java.lang.makeString>.format("%3d", [flex2DArray[y, x]]))
}
out.println()
}
}
to get(r, c) { return storage[r * cols + c] }
to put(r, c, v) { storage[r * cols + c] := v }
}
} |
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #Vlang | Vlang | fn gcd(xx int, yy int) int {
mut x := xx
mut y := yy
for y != 0 {
x, y = y, x%y
}
return x
}
fn yellowstone(n int) []int {
mut m := map[int]bool{}
mut a := []int{len: n+1}
for i in 1..4 {
a[i] = i
m[i] = true
}
mut min := 4
for c := 4; c <= n; c++ {
for i := min; ; i++ {
if !m[i] && gcd(a[c-1], i) == 1 && gcd(a[c-2], i) > 1 {
a[c] = i
m[i] = true
if i == min {
min++
}
break
}
}
}
return a[1..]
}
fn main() {
mut x := []int{len: 100}
for i in 0..100 {
x[i] = i + 1
}
y := yellowstone(100)
println("The first 30 Yellowstone numbers are:")
println(y[..30])
} |
http://rosettacode.org/wiki/Yellowstone_sequence | Yellowstone sequence | The Yellowstone sequence, also called the Yellowstone permutation, is defined as:
For n <= 3,
a(n) = n
For n >= 4,
a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and
is not relatively prime to a(n-2).
The sequence is a permutation of the natural numbers, and gets its name from what its authors felt was a spiking, geyser like appearance of a plot of the sequence.
Example
a(4) is 4 because 4 is the smallest number following 1, 2, 3 in the sequence that is relatively prime to the entry before it (3), and is not relatively prime to the number two entries before it (2).
Task
Find and show as output the first 30 Yellowstone numbers.
Extra
Demonstrate how to plot, with x = n and y coordinate a(n), the first 100 Yellowstone numbers.
Related tasks
Greatest common divisor.
Plot coordinate pairs.
See also
The OEIS entry: A098550 The Yellowstone permutation.
Applegate et al, 2015: The Yellowstone Permutation [1].
| #Wren | Wren | import "/math" for Int
var yellowstone = Fn.new { |n|
var m = {}
var a = List.filled(n + 1, 0)
for (i in 1..3) {
a[i] = i
m[i] = true
}
var min = 4
for (c in 4..n) {
var i = min
while (true) {
if (!m[i] && Int.gcd(a[c-1], i) == 1 && Int.gcd(a[c-2], i) > 1) {
a[c] = i
m[i] = true
if (i == min) min = min + 1
break
}
i = i + 1
}
}
return a[1..-1]
}
var x = List.filled(30, 0)
for (i in 0...30) x[i] = i + 1
var y = yellowstone.call(30)
System.print("The first 30 Yellowstone numbers are:")
System.print(y) |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #OCaml | OCaml | open Num
open Str
open String
let () =
let answer = (Int 5) **/ (Int 4) **/ (Int 3) **/ (Int 2) in
let answer_string = string_of_num answer in
Printf.printf "has %d digits: %s ... %s\n"
(length answer_string)
(first_chars answer_string 20)
(last_chars answer_string 20) |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
{\displaystyle 5^{4^{3^{2}}}}
Confirm that the first and last twenty digits of the answer are:
62060698786608744707...92256259918212890625
Find and show the number of decimal digits in the answer.
Note: Do not submit an implementation of arbitrary precision arithmetic. The intention is to show the capabilities of the language as supplied. If a language has a single, overwhelming, library of varied modules that is endorsed by its home site – such as CPAN for Perl or Boost for C++ – then that may be used instead.
Strictly speaking, this should not be solved by fixed-precision numeric libraries where the precision has to be manually set to a large value; although if this is the only recourse then it may be used with a note explaining that the precision must be set manually to a large enough value.
Related tasks
Long multiplication
Exponentiation order
exponentiation operator
Exponentiation with infix operators in (or operating on) the base
| #Oforth | Oforth | import: mapping
5 4 3 2 pow pow pow >string dup left( 20 ) . dup right( 20 ) . size . |
http://rosettacode.org/wiki/Zeckendorf_number_representation | Zeckendorf number representation | Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series.
Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, 5, 8, 13.
The decimal number eleven can be written as 0*13 + 1*8 + 0*5 + 1*3 + 0*2 + 0*1 or 010100 in positional notation where the columns represent multiplication by a particular member of the sequence. Leading zeroes are dropped so that 11 decimal becomes 10100.
10100 is not the only way to make 11 from the Fibonacci numbers however; 0*13 + 1*8 + 0*5 + 0*3 + 1*2 + 1*1 or 010011 would also represent decimal 11. For a true Zeckendorf number there is the added restriction that no two consecutive Fibonacci numbers can be used which leads to the former unique solution.
Task
Generate and show here a table of the Zeckendorf number representations of the decimal numbers zero to twenty, in order.
The intention in this task to find the Zeckendorf form of an arbitrary integer. The Zeckendorf form can be iterated by some bit twiddling rather than calculating each value separately but leave that to another separate task.
Also see
OEIS A014417 for the the sequence of required results.
Brown's Criterion - Numberphile
Related task
Fibonacci sequence
| #Picat | Picat | go =>
foreach(Num in 0..20)
zeckendorf_cp(Num,X,F),
Nums = [F[I] : I in 1..X.length, X[I] = 1],
printf("%2d %6s %w\n",Num, rep(X),Nums),
end,
nl.
zeckendorf_cp(Num, X,F) =>
F = get_fibs(Num).reverse(),
N = F.length,
X = new_list(N),
X :: 0..1,
% From the task description:
% """
% For a true Zeckendorf number there is the added restriction that
% no two consecutive Fibonacci numbers can be used which leads to
% the former unique solution.
% """
foreach(I in 2..N)
X[I-1] #= 1 #=> X[I] #= 0
end,
scalar_product(F,X,Num),
solve([ff,split],X).
%
% Fibonacci numbers
%
table
fib(0) = 0.
fib(1) = 1.
fib(N) = fib(N-1) + fib(N-2).
%
% Remove leading 0's and stringify it
%
rep(X) = Str =>
First = 1,
if X.length > 1, X[First] = 0 then
while (X[First] == 0)
First := First + 1
end
end,
Str = [X[I].to_string() : I in First..X.length].join('').
%
% Return a list of fibs <= N
%
get_fibs(N) = Fibs =>
I = 2,
Fib = fib(I),
Fibs1 = [Fib],
while (Fib < N)
I := I + 1,
Fib := fib(I),
Fibs1 := Fibs1 ++ [Fib]
end,
Fibs = Fibs1. |
http://rosettacode.org/wiki/Zeckendorf_number_representation | Zeckendorf number representation | Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series.
Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, 5, 8, 13.
The decimal number eleven can be written as 0*13 + 1*8 + 0*5 + 1*3 + 0*2 + 0*1 or 010100 in positional notation where the columns represent multiplication by a particular member of the sequence. Leading zeroes are dropped so that 11 decimal becomes 10100.
10100 is not the only way to make 11 from the Fibonacci numbers however; 0*13 + 1*8 + 0*5 + 0*3 + 1*2 + 1*1 or 010011 would also represent decimal 11. For a true Zeckendorf number there is the added restriction that no two consecutive Fibonacci numbers can be used which leads to the former unique solution.
Task
Generate and show here a table of the Zeckendorf number representations of the decimal numbers zero to twenty, in order.
The intention in this task to find the Zeckendorf form of an arbitrary integer. The Zeckendorf form can be iterated by some bit twiddling rather than calculating each value separately but leave that to another separate task.
Also see
OEIS A014417 for the the sequence of required results.
Brown's Criterion - Numberphile
Related task
Fibonacci sequence
| #PicoLisp | PicoLisp | (de fib (N)
(let Fibs (1 1)
(while (>= N (+ (car Fibs) (cadr Fibs)))
(push 'Fibs (+ (car Fibs) (cadr Fibs))) )
(uniq Fibs) ) )
(de zecken1 (N)
(make
(for I (fib N)
(if (> I N)
(link 0)
(link 1)
(dec 'N I) ) ) ) )
(de zecken2 (N)
(make
(when (=0 N) (link 0))
(for I (fib N)
(when (<= I N)
(link I)
(dec 'N I) ) ) ) )
(for (N 0 (> 21 N) (inc N))
(tab (2 4 6 2 -10)
N
" -> "
(zecken1 N)
" "
(glue " + " (zecken2 N)) ) )
(bye) |
http://rosettacode.org/wiki/100_doors | 100 doors | There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6, ...), and toggle it.
The third time, visit every 3rd door (door #3, #6, #9, ...), etc, until you only visit the 100th door.
Task
Answer the question: what state are the doors in after the last pass? Which are open, which are closed?
Alternate:
As noted in this page's discussion page, the only doors that remain open are those whose numbers are perfect squares.
Opening only those doors is an optimization that may also be expressed;
however, as should be obvious, this defeats the intent of comparing implementations across programming languages.
| #Crystal | Crystal | doors = Array.new(100, false)
1.upto(100) do |i|
i.step(by: i, to: 100) do |j|
doors[j - 1] = !doors[j - 1]
end
end
doors.each_with_index do |open, i|
puts "Door #{i + 1} is #{open ? "open" : "closed"}"
end |
http://rosettacode.org/wiki/Arrays | Arrays | This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retrieve an element (if available, show both fixed-length arrays and
dynamic arrays, pushing a value into it).
Please discuss at Village Pump: Arrays.
Please merge code in from these obsolete tasks:
Creating an Array
Assigning Values to an Array
Retrieving an Element of an Array
Related tasks
Collections
Creating an Associative Array
Two-dimensional array (runtime)
| #GW-BASIC | GW-BASIC | 10 DATA 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
20 DIM A(9) ' Array with size 10 (9 is maximum subscript), all elements are set to 0
30 FOR I = 0 TO 9
40 READ A(I) ' Initialize by reading data
50 NEXT I
60 PRINT A(4) ' Get 4th element of array
70 A(4) = 400 ' Set 4th element of array
80 PRINT A(4)
|
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #Ursala | Ursala | u = 3.785e+00-1.969e+00i
v = 9.545e-01-3.305e+00j
#cast %jL
examples =
<
complex..add (u,v),
complex..mul (u,v),
complex..sub (0.,u),
complex..div (1.,v)> |
http://rosettacode.org/wiki/Arithmetic/Complex | Arithmetic/Complex | A complex number is a number which can be written as:
a
+
b
×
i
{\displaystyle a+b\times i}
(sometimes shown as:
b
+
a
×
i
{\displaystyle b+a\times i}
where
a
{\displaystyle a}
and
b
{\displaystyle b}
are real numbers, and
i
{\displaystyle i}
is √ -1
Typically, complex numbers are represented as a pair of real numbers called the "imaginary part" and "real part", where the imaginary part is the number to be multiplied by
i
{\displaystyle i}
.
Task
Show addition, multiplication, negation, and inversion of complex numbers in separate functions. (Subtraction and division operations can be made with pairs of these operations.)
Print the results for each operation tested.
Optional: Show complex conjugation.
By definition, the complex conjugate of
a
+
b
i
{\displaystyle a+bi}
is
a
−
b
i
{\displaystyle a-bi}
Some languages have complex number libraries available. If your language does, show the operations. If your language does not, also show the definition of this type.
| #VBA | VBA |
Public Type Complex
re As Double
im As Double
End Type
Function CAdd(a As Complex, b As Complex) As Complex
CAdd.re = a.re + b.re
CAdd.im = a.im + b.im
End Function
Function CSub(a As Complex, b As Complex) As Complex
CSub.re = a.re - b.re
CSub.im = a.im - b.im
End Function
Function CMult(a As Complex, b As Complex) As Complex
CMult.re = (a.re * b.re) - (a.im * b.im)
CMult.im = (a.re * b.im) + (a.im * b.re)
End Function
Function CConj(a As Complex) As Complex
CConj.re = a.re
CConj.im = -a.im
End Function
Function CNeg(a As Complex) As Complex
CNeg.re = -a.re
CNeg.im = -a.im
End Function
Function CInv(a As Complex) As Complex
CInv.re = a.re / (a.re * a.re + a.im * a.im)
CInv.im = -a.im / (a.re * a.re + a.im * a.im)
End Function
Function CDiv(a As Complex, b As Complex) As Complex
CDiv = CMult(a, CInv(b))
End Function
Function CAbs(a As Complex) As Double
CAbs = Math.Sqr(a.re * a.re + a.im * a.im)
End Function
Function CSqr(a As Complex) As Complex
CSqr.re = Math.Sqr((a.re + Math.Sqr(a.re * a.re + a.im * a.im)) / 2)
CSqr.im = Math.Sgn(a.im) * Math.Sqr((-a.re + Math.Sqr(a.re * a.re + a.im * a.im)) / 2)
End Function
Function CPrint(a As Complex) As String
If a.im > 0 Then
Sep = "+"
Else
Sep = ""
End If
CPrint = a.re & Sep & a.im & "i"
End Function
Sub ShowComplexCalc()
Dim a As Complex
Dim b As Complex
Dim c As Complex
a.re = 1.5
a.im = 3
b.re = 1.5
b.im = 1.5
Debug.Print "a = " & CPrint(a)
Debug.Print "b = " & CPrint(b)
c = CAdd(a, b)
Debug.Print "a + b = " & CPrint(c)
c = CSub(a, b)
Debug.Print "a - b = " & CPrint(c)
c = CMult(a, b)
Debug.Print "a * b = " & CPrint(c)
c = CConj(a)
Debug.Print "Conj(a) = " & CPrint(c)
c = CNeg(a)
Debug.Print "-a = " & CPrint(c)
c = CInv(a)
Debug.Print "Inv(a) = " & CPrint(c)
c = CDiv(a, b)
Debug.Print "a / b = " & CPrint(c)
Debug.Print "Abs(a) = " & CAbs(a)
c = CSqr(a)
Debug.Print "Sqrt(a) = " & CPrint(c)
End Sub
|
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #Python | Python | from decimal import Decimal
from fractions import Fraction
from itertools import product
zeroes = [0, 0.0, 0j, Decimal(0), Fraction(0, 1), -0.0, -0.0j, Decimal(-0.0)]
for i, j in product(zeroes, repeat=2):
try:
ans = i**j
except:
ans = '<Exception raised>'
print(f'{i!r:>15} ** {j!r:<15} = {ans!r}') |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, you may also try something like:
x = 0
y = 0
z = x**y
say 'z=' z
Show the result here.
And of course use any symbols or notation that is supported in your computer programming language for exponentiation.
See also
The Wiki entry: Zero to the power of zero.
The Wiki entry: History of differing points of view.
The MathWorld™ entry: exponent laws.
Also, in the above MathWorld™ entry, see formula (9):
x
0
=
1
{\displaystyle x^{0}=1}
.
The OEIS entry: The special case of zero to the zeroth power
| #QB64 | QB64 | Print 0 ^ 0 |
http://rosettacode.org/wiki/Zebra_puzzle | Zebra puzzle | Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses.
The English man lives in the red house.
The Swede has a dog.
The Dane drinks tea.
The green house is immediately to the left of the white house.
They drink coffee in the green house.
The man who smokes Pall Mall has birds.
In the yellow house they smoke Dunhill.
In the middle house they drink milk.
The Norwegian lives in the first house.
The man who smokes Blend lives in the house next to the house with cats.
In a house next to the house where they have a horse, they smoke Dunhill.
The man who smokes Blue Master drinks beer.
The German smokes Prince.
The Norwegian lives next to the blue house.
They drink water in a house next to the house where they smoke Blend.
The question is, who owns the zebra?
Additionally, list the solution for all the houses.
Optionally, show the solution is unique.
Related tasks
Dinesman's multiple-dwelling problem
Twelve statements
| #F.23 | F# |
(*Here I solve the Zebra puzzle using Plain Changes, definitely a challenge to some campanoligist to solve it using Grandsire Doubles.
Nigel Galloway: January 27th., 2017 *)
type N = |English=0 |Swedish=1|Danish=2 |German=3|Norwegian=4
type I = |Tea=0 |Coffee=1 |Milk=2 |Beer=3 |Water=4
type G = |Dog=0 |Birds=1 |Cats=2 |Horse=3 |Zebra=4
type E = |Red=0 |Green=1 |White=2 |Blue=3 |Yellow=4
type L = |PallMall=0|Dunhill=1|BlueMaster=2|Prince=3|Blend=4
type NIGELz={Nz:N[];Iz:I[];Gz:G[];Ez:E[];Lz:L[]}
let fn (i:'n[]) g (e:'g[]) l = //coincident?
let rec _fn = function
|5 -> false
|ig when (i.[ig]=g && e.[ig]=l) -> true
|ig -> _fn (ig+1)
_fn 0
let fi (i:'n[]) g (e:'g[]) l = //leftof?
let rec _fn = function
|4 -> false
|ig when (i.[ig]=g && e.[ig+1]=l) -> true
|ig -> _fn (ig+1)
_fn 0
let fg (i:'n[]) g (e:'g[]) l = (fi i g e l || fi e l i g) //adjacent?
let n = Ring.PlainChanges [|for n in System.Enum.GetValues(typeof<N>)->n:?>N|]|>Seq.filter(fun n->n.[0]=N.Norwegian) //#10
let i = Ring.PlainChanges [|for n in System.Enum.GetValues(typeof<I>)->n:?>I|]|>Seq.filter(fun n->n.[2]=I.Milk) //# 9
let g = Ring.PlainChanges [|for n in System.Enum.GetValues(typeof<G>)->n:?>G|]
let e = Ring.PlainChanges [|for n in System.Enum.GetValues(typeof<E>)->n:?>E|]|>Seq.filter(fun n->fi n E.Green n E.White) //# 5
let l = Ring.PlainChanges [|for n in System.Enum.GetValues(typeof<L>)->n:?>L|]
match n|>Seq.map(fun n->{Nz=n;Iz=[||];Gz=[||];Ez=[||];Lz=[||]})
|>Seq.collect(fun n->i|>Seq.map(fun i->{n with Iz=i}))|>Seq.filter(fun n-> fn n.Nz N.Danish n.Iz I.Tea) //# 4
|>Seq.collect(fun n->g|>Seq.map(fun i->{n with Gz=i}))|>Seq.filter(fun n-> fn n.Nz N.Swedish n.Gz G.Dog) //# 3
|>Seq.collect(fun n->e|>Seq.map(fun i->{n with Ez=i}))|>Seq.filter(fun n-> fn n.Nz N.English n.Ez E.Red && //# 2
fn n.Ez E.Green n.Iz I.Coffee&& //# 6
fg n.Nz N.Norwegian n.Ez E.Blue) //#15
|>Seq.collect(fun n->l|>Seq.map(fun i->{n with Lz=i}))|>Seq.tryFind(fun n->fn n.Lz L.PallMall n.Gz G.Birds && //# 7
fg n.Lz L.Blend n.Gz G.Cats && //#11
fn n.Lz L.Prince n.Nz N.German&& //#14
fg n.Lz L.Blend n.Iz I.Water && //#16
fg n.Lz L.Dunhill n.Gz G.Horse && //#12
fn n.Lz L.Dunhill n.Ez E.Yellow&& //# 8
fn n.Iz I.Beer n.Lz L.BlueMaster) with //#13
|Some(nn) -> nn.Gz |> Array.iteri(fun n g -> if (g = G.Zebra) then printfn "\nThe man who owns a zebra is %A\n" nn.Nz.[n]); printfn "%A" nn
|None -> printfn "No solution found"
|
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
| #Groovy | Groovy | def inventory = new XmlSlurper().parseText("<inventory...") //optionally parseText(new File("inv.xml").text)
def firstItem = inventory.section.item[0] //1. first item
inventory.section.item.price.each { println it } //2. print each price
def allNamesArray = inventory.section.item.name.collect {it} //3. collect item names into an array |
http://rosettacode.org/wiki/XML/XPath | XML/XPath | Perform the following three XPath queries on the XML Document below:
//item[1]: Retrieve the first "item" element
//price/text(): Perform an action on each "price" element (print it out)
//name: Get an array of all the "name" elements
XML Document:
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
| #Haskell | Haskell | import Data.List
import Control.Arrow
import Control.Monad
takeWhileIncl :: (a -> Bool) -> [a] -> [a]
takeWhileIncl _ [] = []
takeWhileIncl p (x:xs)
| p x = x : takeWhileIncl p xs
| otherwise = [x]
getmultiLineItem n = takeWhileIncl(not.isInfixOf ("</" ++ n)). dropWhile(not.isInfixOf ('<': n))
getsingleLineItems n = map (takeWhile(/='<'). drop 1. dropWhile(/='>')). filter (isInfixOf ('<': n))
main = do
xml <- readFile "./Rosetta/xmlpath.xml"
let xmlText = lines xml
putStrLn "\n== First item ==\n"
mapM_ putStrLn $ head $ unfoldr (Just. liftM2 (id &&&) (\\) (getmultiLineItem "item")) xmlText
putStrLn "\n== Prices ==\n"
mapM_ putStrLn $ getsingleLineItems "price" xmlText
putStrLn "\n== Names ==\n"
print $ getsingleLineItems "name" xmlText |
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #Icon_and_Unicon | Icon and Unicon | link graphics
procedure main()
YinYang(100)
YinYang(40,"blue","yellow","white")
WDone() # quit on Q/q
end
procedure YinYang(R,lhs,rhs,bg) # draw YinYang with radius of R pixels and ...
/lhs := "white" # left hand side
/rhs := "black" # right hand side
/bg := "grey" # background
wsize := 2*(C := R + (margin := R/5))
W := WOpen("size="||wsize||","||wsize,"bg="||bg) | stop("Unable to open Window")
WAttrib(W,"fg="||lhs) & FillCircle(W,C,C,R,+dtor(90),dtor(180)) # main halves
WAttrib(W,"fg="||rhs) & FillCircle(W,C,C,R,-dtor(90),dtor(180))
WAttrib(W,"fg="||lhs) & FillCircle(W,C,C+R/2,R/2,-dtor(90),dtor(180)) # sub halves
WAttrib(W,"fg="||rhs) & FillCircle(W,C,C-R/2,R/2,dtor(90),dtor(180))
WAttrib(W,"fg="||lhs) & FillCircle(W,C,C-R/2,R/8) # dots
WAttrib(W,"fg="||rhs) & FillCircle(W,C,C+R/2,R/8)
end |
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's state is used in the body of the function.
The Y combinator is itself a stateless function that, when applied to another stateless function, returns a recursive version of the function.
The Y combinator is the simplest of the class of such functions, called fixed-point combinators.
Task
Define the stateless Y combinator and use it to compute factorials and Fibonacci numbers from other stateless functions or lambda expressions.
Cf
Jim Weirich: Adventures in Functional Programming
| #Dhall | Dhall | let const
: ∀(b : Type) → ∀(a : Type) → a → b → a
= λ(r : Type) → λ(a : Type) → λ(x : a) → λ(y : r) → x
let fac
: ∀(n : Natural) → Natural
= λ(n : Natural) →
let factorial =
λ(f : Natural → Natural → Natural) →
λ(n : Natural) →
λ(i : Natural) →
if Natural/isZero i then n else f (i * n) (Natural/subtract 1 i)
in Natural/fold
n
(Natural → Natural → Natural)
factorial
(const Natural Natural)
1
n
let fib
: ∀(n : Natural) → Natural
= λ(n : Natural) →
let fibFunc = Natural → Natural → Natural → Natural
let fibonacci =
λ(f : fibFunc) →
λ(a : Natural) →
λ(b : Natural) →
λ(i : Natural) →
if Natural/isZero i
then a
else f b (a + b) (Natural/subtract 1 i)
in Natural/fold
n
fibFunc
fibonacci
(λ(a : Natural) → λ(_ : Natural) → λ(_ : Natural) → a)
0
1
n
in [fac 50, fib 50] |
http://rosettacode.org/wiki/Zig-zag_matrix | Zig-zag matrix | Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to encode images).
For example, given 5, produce this array:
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24
Related tasks
Spiral matrix
Identity matrix
Ulam spiral (for primes)
See also
Wiktionary entry: anti-diagonals
| #Elena | Elena | import extensions;
extension op : IntNumber
{
zigzagMatrix()
{
auto result := IntMatrix.allocate(self, self);
int i := 0;
int j := 0;
int d := -1;
int start := 0;
int end := self*self - 1;
while (start < end)
{
result.setAt(i, j, start); start += 1;
result.setAt(self - i - 1, self - j - 1, end); end -= 1;
i := i + d;
j := j - d;
if (i < 0)
{
i:=i+1; d := d.Negative
}
else if (j < 0)
{
j := j + 1; d := d.Negative
}
};
if (start == end)
{
result.setAt(i, j, start)
};
^ result
}
}
public program()
{
console.printLine(5.zigzagMatrix()).readChar()
} |
http://rosettacode.org/wiki/Zig-zag_matrix | Zig-zag matrix | Task
Produce a zig-zag array.
A zig-zag array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you zig-zag along the array's anti-diagonals.
For a graphical representation, see JPG zigzag (JPG uses such arrays to encode images).
For example, given 5, produce this array:
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24
Related tasks
Spiral matrix
Identity matrix
Ulam spiral (for primes)
See also
Wiktionary entry: anti-diagonals
| #Elixir | Elixir | defmodule RC do
require Integer
def zigzag(n) do
fmt = "~#{to_char_list(n*n-1) |> length}w "
(for x <- 1..n, y <- 1..n, do: {x,y})
|> Enum.sort_by(fn{x,y}->{x+y, if(Integer.is_even(x+y), do: y, else: x)} end)
|> Enum.with_index |> Enum.sort
|> Enum.each(fn {{_x,y},i} ->
:io.format fmt, [i]
if y==n, do: IO.puts ""
end)
end
end
RC.zigzag(5) |
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