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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
| #PARI.2FGP | PARI/GP | zz(n)={
my(M=matrix(n,n),i,j,d=-1,start,end=n^2-1);
while(ct--,
M[i+1,j+1]=start;
M[n-i,n-j]=end;
start++;
end--;
i+=d;
j-=d;
if(i<0,
i++;
d=-d
,
if(j<0,
j++;
d=-d
)
);
if(start>end,return(M))
)
}; |
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.
| #Fortran | Fortran | program doors
implicit none
integer, allocatable :: door(:)
character(6), parameter :: s(0:1) = [character(6) :: "closed", "open"]
integer :: i, n
print "(A)", "Number of doors?"
read *, n
allocate (door(n))
door = 1
do i = 1, n
door(i:n:i) = 1 - door(i:n:i)
print "(A,G0,2A)", "door ", i, " is ", s(door(i))
end do
end program |
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)
| #MIPS_Assembly | MIPS Assembly |
.data
array: .word 1, 2, 3, 4, 5, 6, 7, 8, 9 # creates an array of 9 32 Bit words.
.text
main: la $s0, array
li $s1, 25
sw $s1, 4($s0) # writes $s1 (25) in the second array element
# the four counts thi bytes after the beginning of the address. 1 word = 4 bytes, so 4 acesses the second element
lw $s2, 20($s0) # $s2 now contains 6
li $v0, 10 # end program
syscall
|
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
| #Phix | Phix | with javascript_semantics
function call_fn(integer f, n)
return call_func(f,{f,n})
end function
function Y(integer f)
return f
end function
function fac(integer self, integer n)
return iff(n>1?n*call_fn(self,n-1):1)
end function
function fib(integer self, integer n)
return iff(n>1?call_fn(self,n-1)+call_fn(self,n-2):n)
end function
procedure test(string name, integer rid=routine_id(name))
integer f = Y(rid)
printf(1,"%s: ",{name})
for i=1 to 10 do
printf(1," %d",call_fn(f,i))
end for
printf(1,"\n");
end procedure
test("fac")
test("fib")
|
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
| #Pascal | Pascal | Program zigzag( input, output );
const
size = 5;
var
zzarray: array [1..size, 1..size] of integer;
element, i, j: integer;
direction: integer;
width, n: integer;
begin
i := 1;
j := 1;
direction := 1;
for element := 0 to (size*size) - 1 do
begin
zzarray[i,j] := element;
i := i + direction;
j := j - direction;
if (i = 0) then
begin
direction := -direction;
i := 1;
if (j > size) then
begin
j := size;
i := 2;
end;
end
else if (i > size) then
begin
direction := -direction;
i := size;
j := j + 2;
end
else if (j = 0) then
begin
direction := -direction;
j := 1;
if (i > size) then
begin
j := 2;
i := size;
end;
end
else if (j > size) then
begin
direction := -direction;
j := size;
i := i + 2;
end;
end;
width := 2;
n := size;
while (n > 0) do
begin
width := width + 1;
n := n div 10;
end;
for j := 1 to size do
begin
for i := 1 to size do
write(zzarray[i,j]:width);
writeln;
end;
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.
| #Free_Pascal | Free Pascal |
program OneHundredIsOpen;
const
DoorCount = 100;
var
IsOpen: array[1..DoorCount] of boolean;
Door, Jump: integer;
begin
// Close all doors
for Door := 1 to DoorCount do
IsOpen[Door] := False;
// Iterations
for Jump := 1 to DoorCount do
begin
Door := Jump;
repeat
IsOpen[Door] := not IsOpen[Door];
Door := Door + Jump;
until Door > DoorCount;
end;
// Show final status
for Door := 1 to DoorCount do
begin
Write(Door, ' ');
if IsOpen[Door] then
WriteLn('open')
else
WriteLn('closed');
end;
// Wait for <enter>
Readln;
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)
| #Modula-2 | Modula-2 | VAR staticArray: ARRAY [1..10] OF INTEGER; |
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
| #Phixmonti | Phixmonti | 0 var subr
def fac
dup 1 > if
dup 1 - subr exec *
endif
enddef
def fib
dup 1 > if
dup 1 - subr exec swap 2 - subr exec +
endif
enddef
def test
print ": " print
var subr
10 for
subr exec print " " print
endfor
nl
enddef
getid fac "fac" test
getid fib "fib" test |
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
| #PHP | PHP | <?php
function Y($f) {
$g = function($w) use($f) {
return $f(function() use($w) {
return call_user_func_array($w($w), func_get_args());
});
};
return $g($g);
}
$fibonacci = Y(function($f) {
return function($i) use($f) { return ($i <= 1) ? $i : ($f($i-1) + $f($i-2)); };
});
echo $fibonacci(10), "\n";
$factorial = Y(function($f) {
return function($i) use($f) { return ($i <= 1) ? 1 : ($f($i - 1) * $i); };
});
echo $factorial(10), "\n";
?> |
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
| #Perl | Perl | use 5.010;
sub zig_zag {
my $n = shift;
my $max_number = $n**2;
my @matrix;
my $number = 0;
for my $j ( 0 .. --$n ) {
for my $i (
$j % 2
? 0 .. $j
: reverse 0 .. $j
)
{
$matrix[$i][ $j - $i ] = $number++;
#next if $j == $n;
$matrix[ $n - $i ][ $n - ( $j - $i ) ] = $max_number - $number;
}
}
return @matrix;
}
my @zig_zag_matrix = zig_zag(5);
say join "\t", @{$_} foreach @zig_zag_matrix;
|
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.
| #FreeBASIC | FreeBASIC | ' version 27-10-2016
' compile with: fbc -s console
#Define max_doors 100
Dim As ULong c, n, n1, door(1 To max_doors)
' toggle, at start all doors are closed (0)
' 0 = door closed, 1 = door open
For n = 1 To max_doors
For n1 = n To max_doors Step n
door(n1) = 1 - door(n1)
Next
Next
' count the doors that are open (1)
Print "doors that are open nr: ";
For n = 1 To max_doors
If door(n) = 1 Then
Print n; " ";
c = c + 1
End If
Next
Print : Print
Print "There are " + Str(c) + " doors open"
' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
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)
| #Modula-3 | Modula-3 | VAR staticArray: ARRAY [1..10] OF INTEGER; |
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
| #PicoLisp | PicoLisp | (de Y (F)
(let X (curry (F) (Y) (F (curry (Y) @ (pass (Y Y)))))
(X X) ) ) |
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
| #Pop11 | Pop11 | define Y(f);
procedure (x); x(x) endprocedure(
procedure (y);
f(procedure(z); (y(y))(z) endprocedure)
endprocedure
)
enddefine;
define fac(h);
procedure (n);
if n = 0 then 1 else n * h(n - 1) endif
endprocedure
enddefine;
define fib(h);
procedure (n);
if n < 2 then 1 else h(n - 1) + h(n - 2) endif
endprocedure
enddefine;
Y(fac)(5) =>
Y(fib)(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
| #Phix | Phix | with javascript_semantics
integer n = 9
integer zstart = 0, zend = n*n-1
--integer zstart = 1, zend = n*n
string fmt = sprintf("%%%dd",length(sprintf("%d",zend)))
sequence m = repeat(repeat("??",n),n)
integer x = 1, y = 1, d = -1
while 1 do
m[x][y] = sprintf(fmt,zstart)
if zstart=zend then exit end if
zstart += 1
m[n-x+1][n-y+1] = sprintf(fmt,zend)
zend -= 1
x += d
y -= d
if x<1 then
x += 1
d = -d
elsif y<1 then
y += 1
d = -d
end if
end while
for i=1 to n do
m[i] = join(m[i])
end for
puts(1,join(m,"\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.
| #friendly_interactive_shell | friendly interactive shell | # Set doors to empty list
set doors
# Initialize doors arrays
for i in (seq 100)
set doors[$i] 0
end
for i in (seq 100)
set j $i
while test $j -le 100
# Logical not on doors
set doors[$j] (math !$doors[$j])
set j (math $j + $i)
end
end
# Print every door
for i in (seq (count $doors))
echo -n "$i "
if test $doors[$i] -eq 0
echo closed
else
echo open
end
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)
| #Monte | Monte | var myArray := ['a', 'b', 'c','d'] |
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
| #PostScript | PostScript | y {
{dup cons} exch concat dup cons i
}.
/fac {
{ {pop zero?} {pop succ} {{dup pred} dip i *} ifte }
y
}. |
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
| #PowerShell | PowerShell | $fac = {
param([ScriptBlock] $f)
invoke-expression @"
{
param([int] `$n)
if (`$n -le 0) {1}
else {`$n * {$f}.InvokeReturnAsIs(`$n - 1)}
}
"@
}
$fib = {
param([ScriptBlock] $f)
invoke-expression @"
{
param([int] `$n)
switch (`$n)
{
0 {1}
1 {1}
default {{$f}.InvokeReturnAsIs(`$n-1)+{$f}.InvokeReturnAsIs(`$n-2)}
}
}
"@
}
$Z = {
param([ScriptBlock] $f)
invoke-expression @"
{
param([ScriptBlock] `$x)
{$f}.InvokeReturnAsIs(`$(invoke-expression @`"
{
param(```$y)
{`$x}.InvokeReturnAsIs({`$x}).InvokeReturnAsIs(```$y)
}
`"@))
}.InvokeReturnAsIs({
param([ScriptBlock] `$x)
{$f}.InvokeReturnAsIs(`$(invoke-expression @`"
{
param(```$y)
{`$x}.InvokeReturnAsIs({`$x}).InvokeReturnAsIs(```$y)
}
`"@))
})
"@
}
$Z.InvokeReturnAsIs($fac).InvokeReturnAsIs(5)
$Z.InvokeReturnAsIs($fib).InvokeReturnAsIs(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
| #Phixmonti | Phixmonti | 5 var Size
0 Size repeat Size repeat
1 var i 1 var j
Size 2 power for
swap i get rot j set i set
i j + 1 bitand 0 == IF
j Size < IF j 1 + var j ELSE i 2 + var i ENDIF
i 1 > IF i 1 - var i ENDIF
ELSE
i Size < IF i 1 + var i ELSE j 2 + var j ENDIF
j 1 > IF j 1 - var j ENDIF
ENDIF
endfor
Size FOR
var row
Size FOR
var col
row get col get tostr 32 32 chain chain 1 3 slice print drop drop
ENDFOR
nl
ENDFOR |
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.
| #Frink | Frink |
doors = new array[[101], false]
for pass=1 to 100
for door=pass to 100 step pass
doors@door = ! doors@door
print["Open doors: "]
for door=1 to 100
if doors@door
print["$door "]
|
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)
| #Nanoquery | Nanoquery | // create a fixed-length array (length 10)
arr = array(10)
// assign a value to the first position in the array and then display it
arr[0] = "hello, world!"
println arr[0]
// create a variable-length list
l = list()
// place the numbers 1-10 in the list
for i in range(1,10)
append l i
end
// display the list
println l |
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
| #Prolog | Prolog | :- use_module(lambda).
% The Y combinator
y(P, Arg, R) :-
Pred = P +\Nb2^F2^call(P,Nb2,F2,P),
call(Pred, Arg, R).
test_y_combinator :-
% code for Fibonacci function
Fib = \NFib^RFib^RFibr1^(NFib < 2 ->
RFib = NFib
;
NFib1 is NFib - 1,
NFib2 is NFib - 2,
call(RFibr1,NFib1,RFib1,RFibr1),
call(RFibr1,NFib2,RFib2,RFibr1),
RFib is RFib1 + RFib2
),
y(Fib, 10, FR), format('Fib(~w) = ~w~n', [10, FR]),
% code for Factorial function
Fact = \NFact^RFact^RFactr1^(NFact = 1 ->
RFact = NFact
;
NFact1 is NFact - 1,
call(RFactr1,NFact1,RFact1,RFactr1),
RFact is NFact * RFact1
),
y(Fact, 10, FF), format('Fact(~w) = ~w~n', [10, FF]). |
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
| #PHP | PHP | function ZigZagMatrix($num) {
$matrix = array();
for ($i = 0; $i < $num; $i++){
$matrix[$i] = array();
}
$i=1;
$j=1;
for ($e = 0; $e < $num*$num; $e++) {
$matrix[$i-1][$j-1] = $e;
if (($i + $j) % 2 == 0) {
if ($j < $num){
$j++;
}else{
$i += 2;
}
if ($i > 1){
$i --;
}
} else {
if ($i < $num){
$i++;
}else{
$j += 2;
}
if ($j > 1){
$j --;
}
}
}
return $matrix;
} |
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.
| #FunL | FunL | for i <- 1..100
r = foldl1( \a, b -> a xor b, [(a|i) | a <- 1..100] )
println( i + ' ' + (if r then 'open' else 'closed') ) |
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)
| #Neko | Neko | var myArray = $array(1);
$print(myArray[0]); |
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
| #Python | Python | >>> Y = lambda f: (lambda x: x(x))(lambda y: f(lambda *args: y(y)(*args)))
>>> fac = lambda f: lambda n: (1 if n<2 else n*f(n-1))
>>> [ Y(fac)(i) for i in range(10) ]
[1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880]
>>> fib = lambda f: lambda n: 0 if n == 0 else (1 if n == 1 else f(n-1) + f(n-2))
>>> [ Y(fib)(i) for i in range(10) ]
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34] |
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
| #PicoLisp | PicoLisp | (load "@lib/simul.l")
(de zigzag (N)
(prog1 (grid N N)
(let (D '(north west south east .) E '(north east .) This 'a1)
(for Val (* N N)
(=: val Val)
(setq This
(or
((cadr D) ((car D) This))
(prog
(setq D (cddr D))
((pop 'E) This) )
((pop 'E) This) ) ) ) ) ) )
(mapc
'((L)
(for This L (prin (align 3 (: val))))
(prinl) )
(zigzag 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
| #PL.2FI | PL/I | /* Fill a square matrix with the values 0 to N**2-1, */
/* in a zig-zag fashion. */
/* N is the length of one side of the square. */
/* Written 22 February 2010. */
declare n fixed binary;
put skip list ('Please type the size of the matrix:');
get list (n);
begin;
declare A(n,n) fixed binary;
declare (i, j, inc, q) fixed binary;
on subrg snap begin;
declare i fixed binary;
do i = 1 to n;
put skip edit (a(i,*)) (f(4));
end;
stop;
end;
A = -1;
inc = -1;
i, j = 1;
loop:
do q = 0 to n**2-1;
a(i,j) = q;
if q = n**2-1 then leave;
if i = 1 & j = n then
if iand(j,1) = 1 then /* odd-sided matrix */
do; i = i + 1; inc = -inc; iterate loop; end;
else /* an even-sided matrix */
do; i = i + inc; j = j - inc; iterate loop; end;
if inc = -1 then if i+inc < 1 then
do; inc = -inc; j = j + 1; a(i,j) = q; iterate loop; end;
if inc = 1 then if i+inc > n then
do; inc = -inc; j = j + 1; a(i,j) = q; iterate loop; end;
if inc = 1 then if j-inc < 1 then
do; inc = -inc; i = i + 1; a(i,j) = q; iterate loop; end;
if inc = -1 then if j - inc > n then
do; inc = -inc; i = i + 1; a(i,j) = q; iterate loop; end;
i = i + inc; j = j - inc;
end;
/* Display the square. */
do i = 1 to n;
put skip edit (a(i,*)) (f(4));
end;
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.
| #Futhark | Futhark |
let main(n: i32): [n]bool =
loop is_open = replicate n false for i < n do
let js = map (*i+1) (iota n)
let flips = map (\j ->
if j < n
then unsafe !is_open[j]
else true -- Doesn't matter.
) js
in scatter is_open js flips
|
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)
| #Nemerle | Nemerle | using System;
using System.Console;
using System.Collections;
module ArrayOps
{
Main() : void
{
def fives = array(10);
foreach (i in [1 .. 10]) fives[i - 1] = i * 5;
def ten = fives[1];
WriteLine($"Ten: $ten");
def dynamic = ArrayList();
dynamic.Add(1);
dynamic.Add(3);
dynamic[1] = 2;
foreach (i in dynamic) Write($"$i\t"); // Nemerle isn't great about displaying arrays, it's better with lists though
}
} |
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's state is used in the body of the function.
The Y combinator is itself a stateless function that, when applied to another stateless function, returns a recursive version of the function.
The Y combinator is the simplest of the class of such functions, called fixed-point combinators.
Task
Define the stateless Y combinator and use it to compute factorials and Fibonacci numbers from other stateless functions or lambda expressions.
Cf
Jim Weirich: Adventures in Functional Programming
| #Q | Q | > Y: {{x x} {({y {(x x) y} x} y) x} x}
> fac: {{$[y<2; 1; y*x y-1]} x}
> (Y fac) 6
720j
> fib: {{$[y<2; 1; (x y-1) + (x y-2)]} x}
> (Y fib) each til 20
1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181 6765
|
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
| #Plain_TeX | Plain TeX | \long\def\antefi#1#2\fi{#2\fi#1}
\def\fornum#1=#2to#3(#4){%
\edef#1{\number\numexpr#2}\edef\fornumtemp{\noexpand\fornumi\expandafter\noexpand\csname fornum\string#1\endcsname
{\number\numexpr#3}{\ifnum\numexpr#4<0 <\else>\fi}{\number\numexpr#4}\noexpand#1}\fornumtemp
}
\long\def\fornumi#1#2#3#4#5#6{\def#1{\unless\ifnum#5#3#2\relax\antefi{#6\edef#5{\number\numexpr#5+(#4)\relax}#1}\fi}#1}
\def\elem(#1,#2){\numexpr(#1+#2)*(#1+#2-1)/2-(\ifodd\numexpr#1+#2\relax#1\else#2\fi)\relax}
\def\zzmat#1{%
\noindent% quit vertical mode
\fornum\yy=1to#1(+1){%
\fornum\xx=1to#1(+1){%
\ifnum\numexpr\xx+\yy\relax<\numexpr#1+2\relax
\hbox to 2em{\hfil\number\elem(\xx,\yy)}%
\else
\hbox to 2em{\hfil\number\numexpr#1*#1-1-\elem(#1+1-\xx,#1+1-\yy)\relax}%
\fi
}%
\par\noindent% next line + quit vertical mode
}\par
}
\zzmat{5}
\bye |
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
| #PostScript | PostScript | %!PS
%%BoundingBox: 0 0 300 200
/size 9 def % defines row * column (9*9 -> 81 numbers,
% from 0 to 80)
/itoa { 2 string cvs } bind def
% visual bounding box...
% 0 0 moveto 300 0 lineto 300 200 lineto 0 200 lineto
% closepath stroke
20 150 translate
% it can be easily enhanced to support more columns and
% rows. This limit is put here just to avoid more than 2
% digits, mainly because of formatting
size size mul 99 le {
/Helvetica findfont 14 scalefont setfont
/ulimit size size mul def
/sizem1 size 1 sub def
% prepare the number list
0 ulimit 1 sub { dup 1 add } repeat
ulimit array astore
/di -1 def /dj 1 def
/ri 1 def /rj 0 def /pus true def
0 0 moveto
/i 0 def /j 0 def
{ % can be rewritten a lot better :)
0.8 setgray i 30 mul j 15 mul neg lineto stroke
0 setgray i 30 mul j 15 mul neg moveto itoa show
i 30 mul j 15 mul neg moveto
pus {
i ri add size ge {
/ri 0 def /rj 1 def
} if
j rj add size ge {
/ri 1 def /rj 0 def
} if
/pus false def
/i i ri add def
/j j rj add def
/ri rj /rj ri def def
} {
i di add dup 0 le
exch sizem1 ge or
j dj add dup 0 le
exch sizem1 ge or
or {
/pus true def
/i i di add def /j j dj add def
/di di neg def /dj dj neg def
} {
/i i di add def /j j dj add def
} ifelse
} ifelse
} forall
stroke showpage
} if
%%EOF |
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.
| #FutureBasic | FutureBasic |
include "NSLog.incl"
NSInteger door, square = 1, increment = 3
for door = 1 to 100
if ( door == square )
NSLog( @"Door %ld is open.", door )
square += increment : increment += 2
else
NSLog( @"Door %ld is closed.", door )
end if
next
HandleEvents
|
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)
| #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref symbols nobinary
array = int[10]
array[0] = 42
say array[0] array[3]
say
words = ['Ogof', 'Ffynnon', 'Ddu']
say words[0] words[1] words[2]
say
-- Dynamic arrays can be simulated via the Java Collections package
splk = ArrayList()
splk.add(words[0])
splk.add(words[1])
splk.add(words[2])
splk.add('Draenen')
say splk.get(0) splk.get(3)
say splk.get(0) splk.get(1) splk.get(2)
say
-- or by using NetRexx "indexed strings" (associative arrays)
cymru = ''
cymru[0] = 0
cymru[0] = cymru[0] + 1; cymru[cymru[0]] = splk.get(0) splk.get(1) splk.get(2)
cymru[0] = cymru[0] + 1; cymru[cymru[0]] = splk.get(0) splk.get(3)
loop x_ = 1 to cymru[0] by 1
say x_':' cymru[x_]
end x_ |
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
| #Quackery | Quackery | [ ' stack nested nested
' share nested join
swap nested join
dup dup 0 peek put ] is recursive ( x --> x )
[ over 2 < iff
[ 2drop 1 ] done
dip [ dup 1 - ] do * ] is factorial ( n x --> n )
[ over 2 < iff drop done
swap 1 - tuck 1 -
over do dip do + ] is fibonacci ( n x --> n )
say "8 factorial = " 8 ' factorial recursive do echo cr
say "8 fibonacci = " 8 ' fibonacci recursive do echo cr |
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
| #PowerShell | PowerShell | function zigzag( [int] $n ) {
$zigzag=New-Object 'Object[,]' $n,$n
$nodd = $n -band 1
$nm1 = $n - 1
$i=0;
$j=0;
foreach( $k in 0..( $n * $n - 1 ) ) {
$zigzag[$i,$j] = $k
$iodd = $i -band 1
$jodd = $j -band 1
if( ( $j -eq $nm1 ) -and ( $iodd -ne $nodd ) ) {
$i++
} elseif( ( $i -eq $nm1 ) -and ( $jodd -eq $nodd ) ) {
$j++
} elseif( ( $i -eq 0 ) -and ( -not $jodd ) ) {
$j++
} elseif( ( $j -eq 0 ) -and $iodd ) {
$i++
} elseif( $iodd -eq $jodd ) {
$i--
$j++
} else {
$i++
$j--
}
}
,$zigzag
}
function displayZigZag( [int] $n ) {
$a = zigzag $n
0..$n | ForEach-Object {
$b=$_
$pad=($n*$n-1).ToString().Length
"$(0..$n | ForEach-Object {
"{0,$pad}" -f $a[$b,$_]
} )"
}
} |
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.
| #FUZE_BASIC | FUZE BASIC | READ x,y,z
PRINT "Open doors: ";x;" ";
CYCLE
z=x+y
PRINT z;" ";
x=z
y=y+2
REPEAT UNTIL z>=100
DATA 1,3,0
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)
| #NewLISP | NewLISP | (array 5)
→ (nil nil nil nil nil) |
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
| #R | R | Y <- function(f) {
(function(x) { (x)(x) })( function(y) { f( (function(a) {y(y)})(a) ) } )
} |
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
| #Racket | Racket | #lang lazy
(define Y (λ (f) ((λ (x) (f (x x))) (λ (x) (f (x x))))))
(define Fact
(Y (λ (fact) (λ (n) (if (zero? n) 1 (* n (fact (- n 1))))))))
(define Fib
(Y (λ (fib) (λ (n) (if (<= n 1) n (+ (fib (- n 1)) (fib (- n 2)))))))) |
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
| #Prolog | Prolog | zig_zag(N) :-
zig_zag(N, N).
% compute zig_zag for a matrix of Lig lines of Col columns
zig_zag(Lig, Col) :-
length(M, Lig),
maplist(init(Col), M),
fill(M, 0, 0, 0, Lig, Col, up),
% display the matrix
maplist(print_line, M).
fill(M, Cur, L, C, NL, NC, _) :-
L is NL - 1,
C is NC - 1,
nth0(L, M, Line),
nth0(C, Line, Cur).
fill(M, Cur, L, C, NL, NC, Sens) :-
nth0(L, M, Line),
nth0(C, Line, Cur),
Cur1 is Cur + 1,
compute_next(NL, NC, L, C, Sens, L1, C1, Sens1),
fill(M, Cur1, L1, C1, NL, NC, Sens1).
init(N, L) :-
length(L, N).
% compute_next
% arg1 : Number of lnes of the matrix
% arg2 : number of columns of the matrix
% arg3 : current line
% arg4 : current column
% arg5 : current direction of movement
% arg6 : nect line
% arg7 : next column
% arg8 : next direction of movement
compute_next(_NL, NC, 0, Col, up, 0, Col1, down) :-
Col < NC - 1,
Col1 is Col+1.
compute_next(_NL, NC, 0, Col, up, 1, Col, down) :-
Col is NC - 1.
compute_next(NL, _NC, Lig, 0, down, Lig1, 0, up) :-
Lig < NL - 1,
Lig1 is Lig+1.
compute_next(NL, _NC, Lig, 0, down, Lig, 1, up) :-
Lig is NL - 1.
compute_next(NL, _NC, Lig, Col, down, Lig1, Col1, down) :-
Lig < NL - 1,
Lig1 is Lig + 1,
Col1 is Col-1.
compute_next(NL, _NC, Lig, Col, down, Lig, Col1, up) :-
Lig is NL - 1,
Col1 is Col+1.
compute_next(_NL, NC, Lig, Col, up, Lig1, Col1, up) :-
Col < NC - 1,
Lig1 is Lig - 1,
Col1 is Col+1.
compute_next(_NL, NC, Lig, Col, up, Lig1, Col, down) :-
Col is NC - 1,
Lig1 is Lig + 1.
print_line(L) :-
maplist(print_val, L),
nl.
print_val(V) :-
writef('%3r ', [V]).
|
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.
| #F.C5.8Drmul.C3.A6 | Fōrmulæ | Public Sub Main()
Dim bDoor As New Boolean[101]
Dim siCount1, siCount2, siStart As Short
For siCount1 = 1 To 100
Inc siStart
For siCount2 = siStart To 100 Step siCount1
bDoor[siCount2] = Not bDoor[siCount2]
Next
Next
For siCount1 = 1 To 100
If bDoor[siCount1] Then Print siCount1;;
Next
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)
| #Nim | Nim | var # fixed size arrays
x = [1,2,3,4,5,6,7,8,9,10] # type and size automatically inferred
y: array[1..5, int] = [1,2,3,4,5] # starts at 1 instead of 0
z: array['a'..'z', int] # indexed using characters
x[0] = x[1] + 1
echo x[0]
echo z['d']
x[7..9] = y[3..5] # copy part of array
var # variable size sequences
a = @[1,2,3,4,5,6,7,8,9,10]
b: seq[int] = @[1,2,3,4,5]
a[0] = a[1] + 1
echo a[0]
a.add(b) # append another sequence
a.add(200) # append another element
echo a.pop() # pop last item, removing and returning it
echo a |
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
| #Raku | Raku | sub Y (&f) { sub (&x) { x(&x) }( sub (&y) { f(sub ($x) { y(&y)($x) }) } ) }
sub fac (&f) { sub ($n) { $n < 2 ?? 1 !! $n * f($n - 1) } }
sub fib (&f) { sub ($n) { $n < 2 ?? $n !! f($n - 1) + f($n - 2) } }
say map Y($_), ^10 for &fac, &fib; |
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
| #PureBasic | PureBasic | Procedure zigZag(size)
Protected i, v, x, y
Dim a(size - 1, size - 1)
x = 1
y = 1
For i = 1 To size * size ;loop once for each element
a(x - 1, y - 1) = v ;assign the next index
If (x + y) & 1 = 0 ;even diagonal (zero based count)
If x < size ;while inside the square
If y > 1 ;move right-up
y - 1
EndIf
x + 1
Else
y + 1 ;on the edge increment y, but not x until diagonal is odd
EndIf
Else ;odd diagonal (zero based count)
If y < size ;while inside the square
If x > 1 ;move left-down
x - 1
EndIf
y + 1
Else
x + 1 ;on the edge increment x, but not y until diagonal is even
EndIf
EndIf
v + 1
Next
;generate and show printout
PrintN("Zig-zag matrix of size " + Str(size) + #CRLF$)
maxDigitCount = Len(Str(size * size)) + 1
For y = 0 To size - 1
For x = 0 To size - 1
Print(RSet(Str(a(x, y)), maxDigitCount, " "))
Next
PrintN("")
Next
PrintN("")
EndProcedure
If OpenConsole()
zigZag(5)
zigZag(6)
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit")
Input()
CloseConsole()
EndIf |
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.
| #Gambas | Gambas | Public Sub Main()
Dim bDoor As New Boolean[101]
Dim siCount1, siCount2, siStart As Short
For siCount1 = 1 To 100
Inc siStart
For siCount2 = siStart To 100 Step siCount1
bDoor[siCount2] = Not bDoor[siCount2]
Next
Next
For siCount1 = 1 To 100
If bDoor[siCount1] Then Print siCount1;;
Next
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)
| #NS-HUBASIC | NS-HUBASIC | 10 DIM A(1)
20 A(1)=10
30 PRINT A(1) |
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
| #REBOL | REBOL | Y: closure [g] [do func [f] [f :f] closure [f] [g func [x] [do f :f :x]]] |
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
| #Python | Python | def zigzag(n):
'''zigzag rows'''
def compare(xy):
x, y = xy
return (x + y, -y if (x + y) % 2 else y)
xs = range(n)
return {index: n for n, index in enumerate(sorted(
((x, y) for x in xs for y in xs),
key=compare
))}
def printzz(myarray):
'''show zigzag rows as lines'''
n = int(len(myarray) ** 0.5 + 0.5)
xs = range(n)
print('\n'.join(
[''.join("%3i" % myarray[(x, y)] for x in xs) for y in xs]
))
printzz(zigzag(6)) |
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.
| #GAP | GAP | doors := function(n)
local a,j,s;
a := [ ];
for j in [1 .. n] do
a[j] := 0;
od;
for s in [1 .. n] do
j := s;
while j <= n do
a[j] := 1 - a[j];
j := j + s;
od;
od;
return Filtered([1 .. n], j -> a[j] = 1);
end;
doors(100);
# [ 1, 4, 9, 16, 25, 36, 49, 64, 81, 100 ] |
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)
| #NSIS | NSIS |
!include NSISArray.nsh
Function ArrayTest
Push $0
; Declaring an array
NSISArray::New TestArray 1 2
NSISArray::Push TestArray "Hello"
; NSISArray arrays are dynamic by default.
NSISArray::Push TestArray "World"
NSISArray::Read TestArray 1
Pop $0
DetailPrint $0
Pop $0
FunctionEnd
|
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
| #REXX | REXX | /*REXX program implements and displays a stateless Y combinator. */
numeric digits 1000 /*allow big numbers. */
say ' fib' Y(fib (50) ) /*Fibonacci series. */
say ' fib' Y(fib (12 11 10 9 8 7 6 5 4 3 2 1 0) ) /*Fibonacci series. */
say ' fact' Y(fact (60) ) /*single factorial.*/
say ' fact' Y(fact (0 1 2 3 4 5 6 7 8 9 10 11) ) /*single factorial.*/
say ' Dfact' Y(dfact (4 5 6 7 8 9 10 11 12 13) ) /*double factorial.*/
say ' Tfact' Y(tfact (4 5 6 7 8 9 10 11 12 13) ) /*triple factorial.*/
say ' Qfact' Y(qfact (4 5 6 7 8 40) ) /*quadruple factorial.*/
say ' length' Y(length (when for to where whenceforth) ) /*lengths of words. */
say 'reverse' Y(reverse (123 66188 3007 45.54 MAS I MA) ) /*reverses strings. */
say ' sign' Y(sign (-8 0 8) ) /*sign of the numbers.*/
say ' trunc' Y(trunc (-7.0005 12 3.14159 6.4 78.999) ) /*truncates numbers. */
say ' b2x' Y(b2x (1 10 11 100 1000 10000 11111 ) ) /*converts BIN──►HEX. */
say ' d2x' Y(d2x (8 9 10 11 12 88 89 90 91 6789) ) /*converts DEC──►HEX. */
say ' x2d' Y(x2d (8 9 10 11 12 88 89 90 91 6789) ) /*converts HEX──►DEC. */
exit 0 /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
Y: parse arg Y _; $=; do j=1 for words(_); interpret '$=$' Y"("word(_,j)')'; end; return $
/*──────────────────────────────────────────────────────────────────────────────────────*/
fib: procedure; parse arg x; if x<2 then return x; s= 0; a= 0; b= 1
do j=2 to x; s= a+b; a= b; b= s; end; return s
/*──────────────────────────────────────────────────────────────────────────────────────*/
dfact: procedure; parse arg x; != 1; do j=x to 2 by -2; != !*j; end; return !
tfact: procedure; parse arg x; != 1; do j=x to 2 by -3; != !*j; end; return !
qfact: procedure; parse arg x; != 1; do j=x to 2 by -4; != !*j; end; return !
fact: procedure; parse arg x; != 1; do j=2 to x ; != !*j; end; return ! |
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
| #Quackery | Quackery | [ ]'[ tuck do dip do ] is with2 ( x x --> x x )
[ dup temp put
[] swap
dup * times [ i^ join ]
sortwith
[ with2
[ temp share /mod
tuck + 1 &
if negate ]
> ]
sortwith
[ with2
[ temp share /mod + ]
> ]
dup witheach
[ i^ unrot poke ]
[] swap
temp share times
[ temp share split
dip [ nested join ] ]
drop
temp release ] is zigzag ( n --> [ )
10 zigzag
witheach
[ witheach
[ dup 10 < if sp
echo sp ]
cr ] |
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
| #Qi | Qi |
(define odd? A -> (= 1 (MOD A 2)))
(define even? A -> (= 0 (MOD A 2)))
(define zigzag-val
0 0 N -> 0
X 0 N -> (1+ (zigzag-val (1- X) 0 N)) where (odd? X)
X 0 N -> (1+ (zigzag-val (1- X) 1 N))
0 Y N -> (1+ (zigzag-val 1 (1- Y) N)) where (odd? Y)
0 Y N -> (1+ (zigzag-val 0 (1- Y) N))
X Y N -> (1+ (zigzag-val (MAX 0 (1- X)) (MIN (1- N) (1+ Y)) N)) where (even? (+ X Y))
X Y N -> (1+ (zigzag-val (MIN (1- N) (1+ X)) (MAX 0 (1- Y)) N)))
(define range
E E -> []
S E -> [S|(range (1+ S) E)])
(define zigzag
N -> (map (/. Y
(map (/. X
(zigzag-val X Y N))
(range 0 N)))
(range 0 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.
| #GDScript | GDScript | func Doors(door_count:int) -> void :
var doors : Array
doors.resize(door_count)
# Note : Initialization is not necessarily mandatory (by default values are false)
# Intentionally left here
for i in door_count :
doors[i] = false
# do visits
for i in door_count :
for j in range(i,door_count,i+1) :
doors[j] = not doors[j]
# print results
var results : String = ""
for i in door_count :
results += str(i+1) + " " if doors[i] else ""
print("Doors open : %s" % [results] )
# calling the function from the _ready function
func _ready() -> void :
Doors(100)
|
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)
| #Oberon-2 | Oberon-2 |
MODULE Arrays;
IMPORT
Out;
PROCEDURE Static;
VAR
x: ARRAY 5 OF LONGINT;
BEGIN
x[0] := 10;
x[1] := 11;
x[2] := 12;
x[3] := 13;
x[4] := x[0];
Out.String("Static at 4: ");Out.LongInt(x[4],0);Out.Ln;
END Static;
PROCEDURE Dynamic;
VAR
x: POINTER TO ARRAY OF LONGINT;
BEGIN
NEW(x,5);
x[0] := 10;
x[1] := 11;
x[2] := 12;
x[3] := 13;
x[4] := x[0];
Out.String("Dynamic at 4: ");Out.LongInt(x[4],0);Out.Ln;
END Dynamic;
BEGIN
Static;
Dynamic
END Arrays.
|
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
| #Ruby | Ruby | y = lambda do |f|
lambda {|g| g[g]}[lambda do |g|
f[lambda {|*args| g[g][*args]}]
end]
end
fac = lambda{|f| lambda{|n| n < 2 ? 1 : n * f[n-1]}}
p Array.new(10) {|i| y[fac][i]} #=> [1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880]
fib = lambda{|f| lambda{|n| n < 2 ? n : f[n-1] + f[n-2]}}
p Array.new(10) {|i| y[fib][i]} #=> [0, 1, 1, 2, 3, 5, 8, 13, 21, 34] |
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
| #R | R | zigzag1 <- function(n) {
j <- seq(n)
u <- rep(c(-1, 1), n)
v <- j * (2 * j - 1) - 1
v <- as.vector(rbind(v, v + 1))
a <- matrix(0, n, n)
for (i in seq(n)) {
a[i, ] <- v[j + i - 1]
v <- v + u
}
a
}
zigzag1(5) |
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.
| #Genie | Genie |
// 100 doors problem
// Author: Sinuhe masan (2019)
init
// 100 elements array of boolean type
doors:bool[100]
for var i = 1 to 100
doors[i] = false // set all doors closed
for var i = 1 to 100
j:int = i
while j <= 100 do
doors[j] = not doors[j]
j = j + i
print("Doors open: ")
for var i = 1 to 100
if doors[i]
stdout.printf ("%d ", i)
|
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)
| #Objeck | Objeck |
bundle Default {
class Arithmetic {
function : Main(args : System.String[]), Nil {
array := Int->New[2];
array[0] := 13;
array[1] := 7;
(array[0] + array[1])->PrintLine();
}
}
}
|
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
| #Rust | Rust |
//! A simple implementation of the Y Combinator:
//! λf.(λx.xx)(λx.f(xx))
//! <=> λf.(λx.f(xx))(λx.f(xx))
/// A function type that takes its own type as an input is an infinite recursive type.
/// We introduce the "Apply" trait, which will allow us to have an input with the same type as self, and break the recursion.
/// The input is going to be a trait object that implements the desired function in the interface.
trait Apply<T, R> {
fn apply(&self, f: &dyn Apply<T, R>, t: T) -> R;
}
/// If we were to pass in self as f, we get:
/// λf.λt.sft
/// => λs.λt.sst [s/f]
/// => λs.ss
impl<T, R, F> Apply<T, R> for F where F: Fn(&dyn Apply<T, R>, T) -> R {
fn apply(&self, f: &dyn Apply<T, R>, t: T) -> R {
self(f, t)
}
}
/// (λt(λx.(λy.xxy))(λx.(λy.f(λz.xxz)y)))t
/// => (λx.xx)(λx.f(xx))
/// => Yf
fn y<T, R>(f: impl Fn(&dyn Fn(T) -> R, T) -> R) -> impl Fn(T) -> R {
move |t| (&|x: &dyn Apply<T, R>, y| x.apply(x, y))
(&|x: &dyn Apply<T, R>, y| f(&|z| x.apply(x, z), y), t)
}
/// Factorial of n.
fn fac(n: usize) -> usize {
let almost_fac = |f: &dyn Fn(usize) -> usize, x| if x == 0 { 1 } else { x * f(x - 1) };
y(almost_fac)(n)
}
/// nth Fibonacci number.
fn fib(n: usize) -> usize {
let almost_fib = |f: &dyn Fn((usize, usize, usize)) -> usize, (a0, a1, x)|
match x {
0 => a0,
1 => a1,
_ => f((a1, a0 + a1, x - 1)),
};
y(almost_fib)((1, 1, n))
}
/// Driver function.
fn main() {
let n = 10;
println!("fac({}) = {}", n, fac(n));
println!("fib({}) = {}", n, fib(n));
}
|
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
| #Racket | Racket |
#lang racket
(define/match (compare i j)
[((list x y) (list a b)) (or (< x a) (and (= x a) (< y b)))])
(define/match (key i)
[((list x y)) (list (+ x y) (if (even? (+ x y)) (- y) y))])
(define (zigzag-ht n)
(define indexorder
(sort (for*/list ([x n] [y n]) (list x y))
compare #:key key))
(for/hash ([(n i) (in-indexed indexorder)]) (values n i)))
(define (zigzag n)
(define ht (zigzag-ht n))
(for/list ([x n])
(for/list ([y n])
(hash-ref ht (list x y)))))
(zigzag 4)
|
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
| #Raku | Raku | class Turtle {
my @dv = [0,-1], [1,-1], [1,0], [1,1], [0,1], [-1,1], [-1,0], [-1,-1];
my $points = 8; # 'compass' points of neighbors on grid: north=0, northeast=1, east=2, etc.
has @.loc = 0,0;
has $.dir = 0;
has %.world;
has $.maxegg;
has $.range-x;
has $.range-y;
method turn-left ($angle = 90) { $!dir -= $angle / 45; $!dir %= $points; }
method turn-right($angle = 90) { $!dir += $angle / 45; $!dir %= $points; }
method lay-egg($egg) {
%!world{~@!loc} = $egg;
$!maxegg max= $egg;
$!range-x minmax= @!loc[0];
$!range-y minmax= @!loc[1];
}
method look($ahead = 1) {
my $there = @!loc »+« @dv[$!dir] »*» $ahead;
%!world{~$there};
}
method forward($ahead = 1) {
my $there = @!loc »+« @dv[$!dir] »*» $ahead;
@!loc = @($there);
}
method showmap() {
my $form = "%{$!maxegg.chars}s";
my $endx = $!range-x.max;
for $!range-y.list X $!range-x.list -> ($y, $x) {
print (%!world{"$x $y"} // '').fmt($form);
print $x == $endx ?? "\n" !! ' ';
}
}
}
sub MAIN(Int $size = 5) {
my $t = Turtle.new(dir => 1);
my $counter = 0;
for 1 ..^ $size -> $run {
for ^$run {
$t.lay-egg($counter++);
$t.forward;
}
my $yaw = $run %% 2 ?? -1 !! 1;
$t.turn-right($yaw * 135); $t.forward; $t.turn-right($yaw * 45);
}
for $size ... 1 -> $run {
for ^$run -> $ {
$t.lay-egg($counter++);
$t.forward;
}
$t.turn-left(180); $t.forward;
my $yaw = $run %% 2 ?? 1 !! -1;
$t.turn-right($yaw * 45); $t.forward; $t.turn-left($yaw * 45);
}
$t.showmap;
} |
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.
| #Glee | Glee | 100` *=0=>d $$ create vector 1..100, create bit pattern d, marking all equal to 0
:for (1..100[.s]){ $$ loop s from 1 to 100
d^(100` %s *=0 )=>d;} $$ d = d xor (bit pattern of vector 1..100 % s)
d $$ output d
|
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)
| #Objective-C | Objective-C | // NSArrays are ordered collections of NSObject subclasses only.
// Create an array of NSString objects.
NSArray *firstArray = [[NSArray alloc] initWithObjects:@"Hewey", @"Louie", @"Dewey", nil];
// NSArrays are immutable; it does have a mutable subclass, however - NSMutableArray.
// Let's instantiate one with a mutable copy of our array.
// We can do this by sending our first array a -mutableCopy message.
NSMutableArray *secondArray = [firstArray mutableCopy];
// Replace Louie with Launchpad McQuack.
[secondArray replaceObjectAtIndex:1 withObject:@"Launchpad"];
// Display the first object in the array.
NSLog(@"%@", [secondArray objectAtIndex:0]);
// In non-ARC or non-GC environments, retained objects must be released later.
[firstArray release];
[secondArray release];
// There is also a modern syntax which allows convenient creation of autoreleased immutable arrays.
// No nil termination is then needed.
NSArray *thirdArray = @[ @"Hewey", @"Louie", @"Dewey", @1, @2, @3 ];
|
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
| #Scala | Scala |
def Y[A, B](f: (A => B) => (A => B)): A => B = {
case class W(wf: W => (A => B)) {
def apply(w: W): A => B = wf(w)
}
val g: W => (A => B) = w => f(w(w))(_)
g(W(g))
}
|
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
| #Rascal | Rascal | 0 (0,0), 1 (0,1), 3 (0,2)
2 (1,0), 4 (1,1), 6 (1,2)
5 (2,0), 7 (2,1), 8 (2,2) |
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
| #REXX | REXX | /*REXX program produces and displays a zig─zag matrix (a square array). */
parse arg n start inc . /*obtain optional arguments from the CL*/
if n=='' | n=="," then n= 5 /*Not specified? Then use the default.*/
if start=='' | start=="," then start= 0 /* " " " " " " */
if inc=='' | inc=="," then inc= 1 /* " " " " " " */
row= 1; col= 1; size= n**2 /*start: 1st row & column; array size.*/
do j=start by inc for size; @.row.col= j
if (row+col)//2==0 then do; if col<n then col= col+1; else row= row+2
if row\==1 then row= row-1
end
else do; if row<n then row= row+1; else col= col+2
if col\==1 then col= col-1
end
end /*j*/ /* [↑] // is REXX ÷ remainder.*/
call show /*display a (square) matrix──►terminal.*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
show: w= max(length(start), length(start+size*inc)) /*max width of any matrix elements,*/
do r=1 for n ; _= right(@.r.1, w) /*show the rows of the matrix. */
do c=2 for n-1; _= _ right(@.r.c, w) /*build a line for output of a row.*/
end /*c*/; say _ /* [↑] align the matrix elements. */
end /*r*/; return |
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.
| #GML | GML | var doors,a,i;
//Sets up the array for all of the doors.
for (i = 1; i<=100; i += 1)
{
doors[i]=0;
}
//This first for loop goes through and passes the interval down to the next for loop.
for (i = 1; i <= 100; i += 1;)
{
//This for loop opens or closes the doors and uses the interval(if interval is 2 it only uses every other etc..)
for (a = 0; a <= 100; a += i;)
{
//Opens or closes a door.
doors[a] = !doors[a];
}
}
open_doors = '';
//This for loop goes through the array and checks for open doors.
//If the door is open it adds it to the string then displays the string.
for (i = 1; i <= 100; i += 1;)
{
if (doors[i] == 1)
{
open_doors += "Door Number "+string(i)+" is open#";
}
}
show_message(open_doors);
game_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)
| #OCaml | OCaml | # Array.make 6 'A' ;;
- : char array = [|'A'; 'A'; 'A'; 'A'; 'A'; 'A'|]
# Array.init 8 (fun i -> i * 10) ;;
- : int array = [|0; 10; 20; 30; 40; 50; 60; 70|]
# let arr = [|0; 1; 2; 3; 4; 5; 6 |] ;;
val arr : int array = [|0; 1; 2; 3; 4; 5; 6|]
# arr.(4) ;;
- : int = 4
# arr.(4) <- 65 ;;
- : unit = ()
# arr ;;
- : int array = [|0; 1; 2; 3; 65; 5; 6|] |
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
| #Scheme | Scheme | (define Y ; (Y f) = (g g) where
(lambda (f) ; (g g) = (f (lambda a (apply (g g) a)))
((lambda (g) (g g)) ; (Y f) == (f (lambda a (apply (Y f) a)))
(lambda (g)
(f (lambda a (apply (g g) a)))))))
;; head-recursive factorial
(define fac ; fac = (Y f) = (f (lambda a (apply (Y f) a)))
(Y (lambda (r) ; = (lambda (x) ... (r (- x 1)) ... )
(lambda (x) ; where r = (lambda a (apply (Y f) a))
(if (< x 2) ; (r ... ) == ((Y f) ... )
1 ; == (lambda (x) ... (fac (- x 1)) ... )
(* x (r (- x 1))))))))
;; tail-recursive factorial
(define fac2
(lambda (x)
((Y (lambda (r) ; (Y f) == (f (lambda a (apply (Y f) a)))
(lambda (x acc) ; r == (lambda a (apply (Y f) a))
(if (< x 2) ; (r ... ) == ((Y f) ... )
acc
(r (- x 1) (* x acc))))))
x 1)))
; double-recursive Fibonacci
(define fib
(Y (lambda (f)
(lambda (x)
(if (< x 2)
x
(+ (f (- x 1)) (f (- x 2))))))))
; tail-recursive Fibonacci
(define fib2
(lambda (x)
((Y (lambda (f)
(lambda (x a b)
(if (< x 1)
a
(f (- x 1) b (+ a b))))))
x 0 1)))
(display (fac 6))
(newline)
(display (fib2 134))
(newline) |
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
| #Ring | Ring |
# Project Zig-zag matrix
load "guilib.ring"
load "stdlib.ring"
new qapp
{
win1 = new qwidget() {
setwindowtitle("Zig-zag matrix")
setgeometry(100,100,600,400)
n = 5
a = newlist(n,n)
zigzag = newlist(n,n)
for j = 1 to n
for i = 1 to n
a[j][i] = 0
next
next
i = 1
j = 1
k = 1
while k < n * n
a[j][i] = k
k = k + 1
if i = n
j = j + 1
a[j][i] = k
k = k + 1
di = -1
dj = 1
ok
if j = 1
i = i + 1
a[j][i] = k
k = k + 1
di = -1
dj = 1
ok
if j = n
i = i + 1
a[j][i] = k
k = k + 1
di = 1
dj = -1
ok
if i = 1
j = j + 1
a[j][i] = k
k = k + 1
di = 1
dj = -1
ok
i = i + di
j = j + dj
end
for p = 1 to n
for m = 1 to n
zigzag[p][m] = new qpushbutton(win1) {
x = 150+m*40
y = 30 + p*40
setgeometry(x,y,40,40)
settext(string(a[p][m]))
}
next
next
show()
}
exec()
}
|
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
| #Ruby | Ruby | def zigzag(n)
(seq=*0...n).product(seq)
.sort_by {|x,y| [x+y, (x+y).even? ? y : -y]}
.each_with_index.sort.map(&:last).each_slice(n).to_a
end
def print_matrix(m)
format = "%#{m.flatten.max.to_s.size}d " * m[0].size
puts m.map {|row| format % row}
end
print_matrix zigzag(5) |
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.
| #Go | Go | package main
import "fmt"
func main() {
doors := [100]bool{}
// the 100 passes called for in the task description
for pass := 1; pass <= 100; pass++ {
for door := pass-1; door < 100; door += pass {
doors[door] = !doors[door]
}
}
// one more pass to answer the question
for i, v := range doors {
if v {
fmt.Print("1")
} else {
fmt.Print("0")
}
if i%10 == 9 {
fmt.Print("\n")
} else {
fmt.Print(" ")
}
}
} |
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)
| #Oforth | Oforth | [ "abd", "def", "ghi" ] at( 3 ) .
Array new dup addAll( [1, 2, 3] ) dup put( 2, 8.1 ) .
|
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
| #Shen | Shen | (define y
F -> ((/. X (X X))
(/. X (F (/. Z ((X X) Z))))))
(let Fac (y (/. F N (if (= 0 N)
1
(* N (F (- N 1))))))
(output "~A~%~A~%~A~%"
(Fac 0)
(Fac 5)
(Fac 10))) |
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
| #Sidef | Sidef | var y = ->(f) {->(g) {g(g)}(->(g) { f(->(*args) {g(g)(args...)})})}
var fac = ->(f) { ->(n) { n < 2 ? 1 : (n * f(n-1)) } }
say 10.of { |i| y(fac)(i) }
var fib = ->(f) { ->(n) { n < 2 ? n : (f(n-2) + f(n-1)) } }
say 10.of { |i| y(fib)(i) } |
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
| #Rust | Rust |
use std::cmp::Ordering;
use std::cmp::Ordering::{Equal, Greater, Less};
use std::iter::repeat;
#[derive(Debug, PartialEq, Eq)]
struct SortIndex {
x: usize,
y: usize,
}
impl SortIndex {
fn new(x: usize, y: usize) -> SortIndex {
SortIndex { x, y }
}
}
impl PartialOrd for SortIndex {
fn partial_cmp(&self, other: &SortIndex) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl Ord for SortIndex {
fn cmp(&self, other: &SortIndex) -> Ordering {
let lower = if self.x + self.y == other.x + other.y {
if (self.x + self.y) % 2 == 0 {
self.x < other.x
} else {
self.y < other.y
}
} else {
(self.x + self.y) < (other.x + other.y)
};
if lower {
Less
} else if self == other {
Equal
} else {
Greater
}
}
}
fn zigzag(n: usize) -> Vec<Vec<usize>> {
let mut l: Vec<SortIndex> = (0..n * n).map(|i| SortIndex::new(i % n, i / n)).collect();
l.sort();
let init_vec = vec![0; n];
let mut result: Vec<Vec<usize>> = repeat(init_vec).take(n).collect();
for (i, &SortIndex { x, y }) in l.iter().enumerate() {
result[y][x] = i
}
result
}
fn main() {
println!("{:?}", zigzag(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
| #Scala | Scala | def zigzag(n: Int): Array[Array[Int]] = {
val l = for (i <- 0 until n*n) yield (i%n, i/n)
val lSorted = l.sortWith {
case ((x,y), (u,v)) =>
if (x+y == u+v)
if ((x+y) % 2 == 0) x<u else y<v
else x+y < u+v
}
val res = Array.ofDim[Int](n, n)
lSorted.zipWithIndex foreach {
case ((x,y), i) => res(y)(x) = i
}
res
}
zigzag(5).foreach{
ar => ar.foreach(x => print("%3d".format(x)))
println
} |
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.
| #Golfscript | Golfscript | 100:c;[{0}c*]:d;
c,{.c,>\)%{.d<\.d=1^\)d>++:d;}/}/
[c,{)"door "\+" is"+}%d{{"open"}{"closed"}if}%]zip
{" "*puts}/ |
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)
| #Ol | Ol |
; making a vector
> #(1 2 3 4 5)
#(1 2 3 4 5)
; making a vector in a functional way
> (vector 1 2 3 4 5)
#(1 2 3 4 5)
; another functional vector making way
> (make-vector '(1 2 3 4 5))
#(1 2 3 4 5)
; the same as above functional vector making way
> (list->vector '(1 2 3 4 5))
#(1 2 3 4 5)
; modern syntax of making a vector
> [1 2 3 4 5]
#(1 2 3 4 5)
; making a vector of symbols
> '[a b c d e]
#(a b c d e)
; making a vector of symbols but evaluate a third element
> `[a b ,(* 7 13) d e]
#(a b 91 d e)
; making an empty vectors
> #()
#()
> []
#()
> '[]
#()
> `[]
#()
> (make-vector '())
#()
> (list->vector '())
#()
; making a vector of a vectors (a matrix, for example)
> [[1 2 3]
[4 5 6]
[7 8 9]]
#(#(1 2 3) #(4 5 6) #(7 8 9))
; getting length of a vector
> (size [1 2 3 4 5])
5
; making n-length vector with undefined values (actually, #false)
> (make-vector 5)
#(#false #false #false #false #false)
; making n-length vector with default values
> (make-vector 5 0)
#(0 0 0 0 0)
; define a test vector for use in below
> (define array [3 5 7 9 11])
;; Defined array
; getting first element of a vector
> (ref array 1)
3
> (ref array (- (size array)))
3
; getting last element of a vector
> (ref array (size array))
11
> (ref array -1)
11
; vectors comparison
> (equal? [1 2 3 4 5] [1 2 3 4 5])
#true
> (equal? [1 2 3 4 5] [7 2 3 4 5])
#false
; vectors of vectors comparison
> (equal?
[[1 2 3]
[4 5 6]
[7 8 9]]
[[1 2 3]
[4 5 6]
[7 8 9]])
#true
> (equal?
[[1 2 3]
[4 5 6]
[7 8 9]]
[[1 2 3]
[4 5 6]
[7 8 3]])
#false
|
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
| #Slate | Slate | Method traits define: #Y &builder:
[[| :f | [| :x | f applyWith: (x applyWith: x)]
applyWith: [| :x | f applyWith: (x applyWith: x)]]]. |
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
| #Scilab | Scilab | function a = zigzag3(n)
a = zeros(n, n)
for k=1:n
j = modulo(k, 2)
d = (2*j-1)*(n-1)
m = (n-1)*(k-1)
a(k+(1-j)*m:d:k+j*m) = k*(k-1)/2:k*(k+1)/2-1
a(n*(n+1-k)+(1-j)*m:d:n*(n+1-k)+j*m) = n*n-k*(k+1)/2:n*n-k*(k-1)/2-1
end
endfunction
-->zigzag3(5)
ans =
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. |
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.
| #Gosu | Gosu |
uses java.util.Arrays
var doors = new boolean[100]
Arrays.fill( doors, false )
for( pass in 1..100 ) {
var counter = pass-1
while( counter < 100 ) {
doors[counter] = !doors[counter]
counter += pass
}
}
for( door in doors index i ) {
print( "door ${i+1} is ${door ? 'open' : 'closed'}" )
}
|
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)
| #ooRexx | ooRexx | a = .array~new -- create a zero element array
b = .array~new(10) -- create an array with initial size of 10
c = .array~of(1, 2, 3) -- create a 3 element array holding objects 1, 2, and 3
a[3] = "Fred" -- assign an item
b[2] = a[3] -- retrieve an item from the array
c~append(4) -- adds to end. c[4] == 4 now |
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
| #Smalltalk | Smalltalk | Y := [:f| [:x| x value: x] value: [:g| f value: [:x| (g value: g) value: x] ] ].
fib := Y value: [:f| [:i| i <= 1 ifTrue: [i] ifFalse: [(f value: i-1) + (f value: i-2)] ] ].
(fib value: 10) displayNl.
fact := Y value: [:f| [:i| i = 0 ifTrue: [1] ifFalse: [(f value: i-1) * i] ] ].
(fact value: 10) displayNl. |
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
| #Seed7 | Seed7 | $ include "seed7_05.s7i";
const type: matrix is array array integer;
const func matrix: zigzag (in integer: size) is func
result
var matrix: s is matrix.value;
local
var integer: i is 1;
var integer: j is 1;
var integer: d is -1;
var integer: max is 0;
var integer: n is 0;
begin
s := size times size times 0;
max := size ** 2;
for n range 1 to max div 2 + 1 do
s[i][j] := n;
s[size - i + 1][size - j + 1] := max - n + 1;
i +:= d;
j -:= d;
if i < 1 then
incr(i);
d := -d;
elsif j < 1 then
incr(j);
d := -d;
end if;
end for;
end func;
const proc: main is func
local
var matrix: s is matrix.value;
var integer: i is 0;
var integer: num is 0;
begin
s := zigzag(7);
for i range 1 to length(s) do
for num range s[i] do
write(num lpad 4);
end for;
writeln;
end for;
end func; |
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
| #Sidef | Sidef | func zig_zag(w, h) {
var r = []
var n = 0
h.of { |e|
w.of { |f|
[e, f]
}
}.reduce('+').sort { |a, b|
(a[0]+a[1] <=> b[0]+b[1]) ||
(a[0]+a[1] -> is_even ? a[0]<=>b[0]
: a[1]<=>b[1])
}.each { |a|
r[a[1]][a[0]] = n++
}
return r
}
zig_zag(5, 5).each { say .join('', {|i| "%4i" % i}) } |
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.
| #Groovy | Groovy | doors = [false] * 100
(0..99).each {
it.step(100, it + 1) {
doors[it] ^= true
}
}
(0..99).each {
println("Door #${it + 1} is ${doors[it] ? 'open' : 'closed'}.")
} |
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)
| #OxygenBasic | OxygenBasic |
'CREATING A STATIC ARRAY
float f[100]
'SETTING INDEX BASE
indexbase 1 'default
'FILLING PART OF AN ARRAY
f[20]={2,4,6,8,10,12}
'MAPPING AN ARRAY TO ANOTHER
float *g
@g=@f[20]
print g[6] 'result 12
'DYNAMIC (RESIZEABLE) ARRAYS
redim float f(100)
f={2,4,6,8} 'assign some values
redim float f(200) 'expand array
print f(2) 'original values are preserved by default
redim float f(200) clear 'array elements are cleared
print f(2) 'value set to 0.0
redim float f(0) 'release allocated memory '
|
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
| #Standard_ML | Standard ML | - datatype 'a mu = Roll of ('a mu -> 'a)
fun unroll (Roll x) = x
fun fix f = (fn x => fn a => f (unroll x x) a) (Roll (fn x => fn a => f (unroll x x) a))
fun fac f 0 = 1
| fac f n = n * f (n-1)
fun fib f 0 = 0
| fib f 1 = 1
| fib f n = f (n-1) + f (n-2)
;
datatype 'a mu = Roll of 'a mu -> 'a
val unroll = fn : 'a mu -> 'a mu -> 'a
val fix = fn : (('a -> 'b) -> 'a -> 'b) -> 'a -> 'b
val fac = fn : (int -> int) -> int -> int
val fib = fn : (int -> int) -> int -> int
- List.tabulate (10, fix fac);
val it = [1,1,2,6,24,120,720,5040,40320,362880] : int list
- List.tabulate (10, fix fib);
val it = [0,1,1,2,3,5,8,13,21,34] : int list |
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
| #Standard_ML | Standard ML | fun rowprint r = (List.app (fn i => print (StringCvt.padLeft #" " 3 (Int.toString i))) r;
print "\n");
fun zig lst M = List.app rowprint (lst M);
fun sign t = if t mod 2 = 0 then ~1 else 1;
fun zag n = List.tabulate (n,
fn i=> rev ( List.tabulate (n,
fn j =>
let val t = n-j+i and u = n+j-i in
if i <= j
then t*t div 2 + sign t * ( t div 2 - i )
else n*n - 1 - ( u*u div 2 + sign u * ( u div 2 - n + 1 + i) )
end
)));
zig zag 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
| #Stata | Stata | function zigzag1(n) {
j = 0::n-1
u = J(1, n, (-1, 1))
v = (j:*(2:*j:+3))
v = rowshape((v,v:+1), 1)
a = J(n, n, .)
for (i=1; i<=n; i++) {
a[i, .] = v[j:+i]
v = v+u
}
return(a)
}
zigzag1(5)
1 2 3 4 5
+--------------------------+
1 | 0 1 5 6 14 |
2 | 2 4 7 13 16 |
3 | 3 8 12 17 25 |
4 | 9 11 18 24 31 |
5 | 10 19 23 32 40 |
+--------------------------+ |
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.
| #GW-BASIC | GW-BASIC | 10 DIM A(100)
20 FOR OFFSET = 1 TO 100
30 FOR I = 0 TO 100 STEP OFFSET
40 A(I) = A(I) + 1
50 NEXT I
60 NEXT OFFSET
70 ' Print "opened" doors
80 FOR I = 1 TO 100
90 IF A(I) MOD 2 = 1 THEN PRINT I
100 NEXT I |
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)
| #Oz | Oz | declare
Arr = {Array.new 1 %% lowest index
10 %% highest index
37} %% all 10 fields initialized to 37
in
{Show Arr.1}
Arr.1 := 64
{Show Arr.1} |
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
| #SuperCollider | SuperCollider | // z-combinator
(
z = { |f|
{ |x| x.(x) }.(
{ |y|
f.({ |args| y.(y).(args) })
}
)
};
)
// the same in a shorter form
(
r = { |x| x.(x) };
z = { |f| r.({ |y| f.(r.(y).(_)) }) };
)
// factorial
k = { |f| { |x| if(x < 2, 1, { x * f.(x - 1) }) } };
g = z.(k);
g.(5) // 120
(1..10).collect(g) // [ 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800 ]
// fibonacci
k = { |f| { |x| if(x <= 2, 1, { f.(x - 1) + f.(x - 2) }) } };
g = z.(k);
g.(3)
(1..10).collect(g) // [ 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
| #Tcl | Tcl | proc zigzag {size} {
set m [lrepeat $size [lrepeat $size .]]
set x 0; set dx -1
set y 0; set dy 1
for {set i 0} {$i < $size ** 2} {incr i} {
if {$x >= $size} {
incr x -1
incr y 2
negate dx dy
} elseif {$y >= $size} {
incr x 2
incr y -1
negate dx dy
} elseif {$x < 0 && $y >= 0} {
incr x
negate dx dy
} elseif {$x >= 0 && $y < 0} {
incr y
negate dx dy
}
lset m $x $y $i
incr x $dx
incr y $dy
}
return $m
}
proc negate {args} {
foreach varname $args {
upvar 1 $varname var
set var [expr {-1 * $var}]
}
}
print_matrix [zigzag 5] |
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.
| #Harbour | Harbour | #define ARRAY_ELEMENTS 100
PROCEDURE Main()
LOCAL aDoors := Array( ARRAY_ELEMENTS )
LOCAL i, j
AFill( aDoors, .F. )
FOR i := 1 TO ARRAY_ELEMENTS
FOR j := i TO ARRAY_ELEMENTS STEP i
aDoors[ j ] = ! aDoors[ j ]
NEXT
NEXT
AEval( aDoors, {|e, n| QQout( Padl(n,3) + " is " + Iif(aDoors[n], "*open*", "closed" ) + "|" ), Iif( n%5 == 0, Qout(), e:=NIL) } )
RETURN |
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