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http://rosettacode.org/wiki/Verify_distribution_uniformity/Naive | Verify distribution uniformity/Naive | This task is an adjunct to Seven-sided dice from five-sided dice.
Task
Create a function to check that the random integers returned from a small-integer generator function have uniform distribution.
The function should take as arguments:
The function (or object) producing random integers.
The number of times to call the integer generator.
A 'delta' value of some sort that indicates how close to a flat distribution is close enough.
The function should produce:
Some indication of the distribution achieved.
An 'error' if the distribution is not flat enough.
Show the distribution checker working when the produced distribution is flat enough and when it is not. (Use a generator from Seven-sided dice from five-sided dice).
See also:
Verify distribution uniformity/Chi-squared test
| #zkl | zkl | fcn rtest(N){
dist:=L(0,0,0,0,0,0,0,0,0,0);
do(N){n:=(0).random(10); dist[n]=dist[n]+1}
sum:=dist.sum();
dist=dist.apply('wrap(n){n.toFloat()/sum*100});
if (dist.filter((10.0).closeTo.fp1(0.1)).len() == 10)
{ "Good enough at %,d: %s".fmt(N,dist).println(); return(True); }
False
}
n:=10;
while(not rtest(n)) {n*=2} |
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #J | J | 1+I.(}:=}.) 1 2 2 3 4 4 5
2 5 |
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #Java | Java | public class VariableDeclarationReset {
public static void main(String[] args) {
int[] s = {1, 2, 2, 3, 4, 4, 5};
// There is no output as 'prev' is created anew each time
// around the loop and set to zero.
for (int i = 0; i < s.length; ++i) {
int curr = s[i];
int prev = 0;
// int prev; // triggers "error: variable prev might not have been initialized"
if (i > 0 && curr == prev) System.out.println(i);
prev = curr;
}
int gprev = 0;
// Now 'gprev' is used and reassigned
// each time around the loop producing the desired output.
for (int i = 0; i < s.length; ++i) {
int curr = s[i];
if (i > 0 && curr == gprev) System.out.println(i);
gprev = curr;
}
}
} |
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #JavaScript | JavaScript | <!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="utf-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>variable declaration reset</title>
</head>
<body>
<script>
"use strict";
let s = [1, 2, 2, 3, 4, 4, 5];
for (let i=0; i<7; i+=1) {
let curr = s[i], prev;
if (i>0 && (curr===prev)) {
console.log(i);
}
prev = curr;
}
</script>
</body>
</html> |
http://rosettacode.org/wiki/Van_der_Corput_sequence | Van der Corput sequence | When counting integers in binary, if you put a (binary) point to the righEasyLangt of the count then the column immediately to the left denotes a digit with a multiplier of
2
0
{\displaystyle 2^{0}}
; the digit in the next column to the left has a multiplier of
2
1
{\displaystyle 2^{1}}
; and so on.
So in the following table:
0.
1.
10.
11.
...
the binary number "10" is
1
×
2
1
+
0
×
2
0
{\displaystyle 1\times 2^{1}+0\times 2^{0}}
.
You can also have binary digits to the right of the “point”, just as in the decimal number system. In that case, the digit in the place immediately to the right of the point has a weight of
2
−
1
{\displaystyle 2^{-1}}
, or
1
/
2
{\displaystyle 1/2}
.
The weight for the second column to the right of the point is
2
−
2
{\displaystyle 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
. And so on.
If you take the integer binary count of the first table, and reflect the digits about the binary point, you end up with the van der Corput sequence of numbers in base 2.
.0
.1
.01
.11
...
The third member of the sequence, binary 0.01, is therefore
0
×
2
−
1
+
1
×
2
−
2
{\displaystyle 0\times 2^{-1}+1\times 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
.
Distribution of 2500 points each: Van der Corput (top) vs pseudorandom
0
≤
x
<
1
{\displaystyle 0\leq x<1}
Monte Carlo simulations
This sequence is also a superset of the numbers representable by the "fraction" field of an old IEEE floating point standard. In that standard, the "fraction" field represented the fractional part of a binary number beginning with "1." e.g. 1.101001101.
Hint
A hint at a way to generate members of the sequence is to modify a routine used to change the base of an integer:
>>> def base10change(n, base):
digits = []
while n:
n,remainder = divmod(n, base)
digits.insert(0, remainder)
return digits
>>> base10change(11, 2)
[1, 0, 1, 1]
the above showing that 11 in decimal is
1
×
2
3
+
0
×
2
2
+
1
×
2
1
+
1
×
2
0
{\displaystyle 1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+1\times 2^{0}}
.
Reflected this would become .1101 or
1
×
2
−
1
+
1
×
2
−
2
+
0
×
2
−
3
+
1
×
2
−
4
{\displaystyle 1\times 2^{-1}+1\times 2^{-2}+0\times 2^{-3}+1\times 2^{-4}}
Task description
Create a function/method/routine that given n, generates the n'th term of the van der Corput sequence in base 2.
Use the function to compute and display the first ten members of the sequence. (The first member of the sequence is for n=0).
As a stretch goal/extra credit, compute and show members of the sequence for bases other than 2.
See also
The Basic Low Discrepancy Sequences
Non-decimal radices/Convert
Van der Corput sequence
| #360_Assembly | 360 Assembly | * Van der Corput sequence 31/01/2017
VDCS CSECT
USING VDCS,R13 base register
B 72(R15) skip savearea
DC 17F'0' savearea
STM R14,R12,12(R13) prolog
ST R13,4(R15) " <-
ST R15,8(R13) " ->
LR R13,R15 " addressability
ZAP B,=P'2' b=2 (base)
ZAP M,=P'-1' m=-1
SR R6,R6 i=0
LOOPI CH R6,=H'10' do i=0 to 10
BH ELOOPI
AP M,=P'1' w=m+1
ZAP V,=P'0' v=0
ZAP S,=P'1' s=1
ZAP N,M n=m
WHILE CP N,=P'0' do while n<>0
BE EWHILE
MP S,B s=s*b
ZAP PL16,N n
DP PL16,B n/b
ZAP W,PL16+8(8) w=n mod b
MP W,=P'100000' *100000
ZAP PL16,W w
DP PL16,S w/s
ZAP W,PL16(8) w=w/s
AP V,W v=v+(n mod b)*100000/s
ZAP PL16,N n
DP PL16,B n/b
ZAP N,PL16(8) n=n/b
B WHILE
EWHILE XDECO R6,XDEC edit i
MVC PG+0(3),XDEC+9 output i
MVC PG+3(3),=C' 0.'
UNPK Z,V unpack v
OI Z+L'Z-1,X'F0' edit v
MVC PG+6(5),Z+11 output v (v/100000)
XPRNT PG,L'PG print buffer
LA R6,1(R6) i=i+1
B LOOPI
ELOOPI L R13,4(0,R13) epilog
LM R14,R12,12(R13) " restore
XR R15,R15 " rc=0
BR R14 exit
B DS PL8
M DS PL8
V DS PL8
S DS PL8
N DS PL8
W DS PL8 packed
Z DS ZL16 zoned
PL16 DS PL16 packed max
PG DC CL80' ' buffer
XDEC DS CL12 work area for xdeco
YREGS
END VDCS |
http://rosettacode.org/wiki/Van_der_Corput_sequence | Van der Corput sequence | When counting integers in binary, if you put a (binary) point to the righEasyLangt of the count then the column immediately to the left denotes a digit with a multiplier of
2
0
{\displaystyle 2^{0}}
; the digit in the next column to the left has a multiplier of
2
1
{\displaystyle 2^{1}}
; and so on.
So in the following table:
0.
1.
10.
11.
...
the binary number "10" is
1
×
2
1
+
0
×
2
0
{\displaystyle 1\times 2^{1}+0\times 2^{0}}
.
You can also have binary digits to the right of the “point”, just as in the decimal number system. In that case, the digit in the place immediately to the right of the point has a weight of
2
−
1
{\displaystyle 2^{-1}}
, or
1
/
2
{\displaystyle 1/2}
.
The weight for the second column to the right of the point is
2
−
2
{\displaystyle 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
. And so on.
If you take the integer binary count of the first table, and reflect the digits about the binary point, you end up with the van der Corput sequence of numbers in base 2.
.0
.1
.01
.11
...
The third member of the sequence, binary 0.01, is therefore
0
×
2
−
1
+
1
×
2
−
2
{\displaystyle 0\times 2^{-1}+1\times 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
.
Distribution of 2500 points each: Van der Corput (top) vs pseudorandom
0
≤
x
<
1
{\displaystyle 0\leq x<1}
Monte Carlo simulations
This sequence is also a superset of the numbers representable by the "fraction" field of an old IEEE floating point standard. In that standard, the "fraction" field represented the fractional part of a binary number beginning with "1." e.g. 1.101001101.
Hint
A hint at a way to generate members of the sequence is to modify a routine used to change the base of an integer:
>>> def base10change(n, base):
digits = []
while n:
n,remainder = divmod(n, base)
digits.insert(0, remainder)
return digits
>>> base10change(11, 2)
[1, 0, 1, 1]
the above showing that 11 in decimal is
1
×
2
3
+
0
×
2
2
+
1
×
2
1
+
1
×
2
0
{\displaystyle 1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+1\times 2^{0}}
.
Reflected this would become .1101 or
1
×
2
−
1
+
1
×
2
−
2
+
0
×
2
−
3
+
1
×
2
−
4
{\displaystyle 1\times 2^{-1}+1\times 2^{-2}+0\times 2^{-3}+1\times 2^{-4}}
Task description
Create a function/method/routine that given n, generates the n'th term of the van der Corput sequence in base 2.
Use the function to compute and display the first ten members of the sequence. (The first member of the sequence is for n=0).
As a stretch goal/extra credit, compute and show members of the sequence for bases other than 2.
See also
The Basic Low Discrepancy Sequences
Non-decimal radices/Convert
Van der Corput sequence
| #Action.21 | Action! | INCLUDE "D2:REAL.ACT" ;from the Action! Tool Kit
PROC Generate(INT value,base REAL POINTER res)
REAL denom,rbase,r1,r2
IntToReal(0,res)
IntToReal(1,denom)
IntToReal(base,rbase)
WHILE value#0
DO
RealMult(denom,rbase,r1)
RealAssign(r1,denom)
IntToReal(value MOD base,r1)
RealDiv(r1,denom,r2)
RealAdd(res,r2,r1)
RealAssign(r1,res)
value==/base
OD
RETURN
PROC Main()
INT value,base
REAL res
Put(125) PutE() ;clear the screen
FOR base=2 TO 5
DO
PrintF("Base %I:%E",base)
FOR value=0 TO 9
DO
Generate(value,base,res)
PrintR(res) Put(32)
OD
PutE() PutE()
OD
RETURN |
http://rosettacode.org/wiki/Variables | Variables | Task
Demonstrate a language's methods of:
variable declaration
initialization
assignment
datatypes
scope
referencing, and
other variable related facilities
| #8086_Assembly | 8086 Assembly | .data
MyVar word 0FFFFh ;the leading zero is just to help the assembler tell that this is a number, it's not actually part of the variable.
.code
mov ax, word ptr [ds:MyVar] |
http://rosettacode.org/wiki/Variables | Variables | Task
Demonstrate a language's methods of:
variable declaration
initialization
assignment
datatypes
scope
referencing, and
other variable related facilities
| #8th | 8th |
\ declare a variable which is initialized to the number '0'
var x
\ declare a variable which is initialized to a string "cat"
"cat" var, y
\ Get the value in x, add 20 and store it:
x @ 20 n:+ x !
\ Change the cat to a dog:
"dog" y !
|
http://rosettacode.org/wiki/Van_Eck_sequence | Van Eck sequence | The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occured previously.
Example
Using A:
0
Using B:
0 0
Using C:
0 0 1
Using B:
0 0 1 0
Using C: (zero last occurred two steps back - before the one)
0 0 1 0 2
Using B:
0 0 1 0 2 0
Using C: (two last occurred two steps back - before the zero)
0 0 1 0 2 0 2 2
Using C: (two last occurred one step back)
0 0 1 0 2 0 2 2 1
Using C: (one last appeared six steps back)
0 0 1 0 2 0 2 2 1 6
...
Task
Create a function/procedure/method/subroutine/... to generate the Van Eck sequence of numbers.
Use it to display here, on this page:
The first ten terms of the sequence.
Terms 991 - to - 1000 of the sequence.
References
Don't Know (the Van Eck Sequence) - Numberphile video.
Wikipedia Article: Van Eck's Sequence.
OEIS sequence: A181391.
| #Ada | Ada | with Ada.Text_IO;
procedure Van_Eck_Sequence is
Sequence : array (Natural range 1 .. 1_000) of Natural;
procedure Calculate_Sequence is
begin
Sequence (Sequence'First) := 0;
for Index in Sequence'First .. Sequence'Last - 1 loop
Sequence (Index + 1) := 0;
for I in reverse Sequence'First .. Index - 1 loop
if Sequence (I) = Sequence (Index) then
Sequence (Index + 1) := Index - I;
exit;
end if;
end loop;
end loop;
end Calculate_Sequence;
procedure Show (First, Last : in Positive) is
use Ada.Text_IO;
begin
Put ("Element" & First'Image & " .." & Last'Image & " of Van Eck sequence: ");
for I in First .. Last loop
Put (Sequence (I)'Image);
end loop;
New_Line;
end Show;
begin
Calculate_Sequence;
Show (First => 1, Last => 10);
Show (First => 991, Last => 1_000);
end Van_Eck_Sequence; |
http://rosettacode.org/wiki/Vampire_number | Vampire number | A vampire number is a natural decimal number with an even number of digits, that can be factored into two integers.
These two factors are called the fangs, and must have the following properties:
they each contain half the number of the decimal digits of the original number
together they consist of exactly the same decimal digits as the original number
at most one of them has a trailing zero
An example of a vampire number and its fangs: 1260 : (21, 60)
Task
Print the first 25 vampire numbers and their fangs.
Check if the following numbers are vampire numbers and, if so, print them and their fangs:
16758243290880, 24959017348650, 14593825548650
Note that a vampire number can have more than one pair of fangs.
See also
numberphile.com.
vampire search algorithm
vampire numbers on OEIS
| #Bracmat | Bracmat | ( ( vampire
= N len R fangsList
. !arg:@(?N:? [?len)
& 1/2*!len:~/:?len
& ( R
= len numpart left right allowed fangs rdigits
, tried digit untried head tail found
. !arg:(?len.?left.?numpart.?allowed)
& :?found
& ( !len:>0
& ( @( !numpart
: ?tried
( #%@?digit
& !allowed:?head !digit ?tail
& !head !tail:?allowed
)
( ?untried
& R
$ ( !len+-1
. 10*!left+!digit
. str$(!tried !untried)
. 0 1 2 3 4 5 6 7 8 9
)
: ?fangs
& !found !fangs:?found
& ~
)
)
| !found
)
| !N*!left^-1:~/?right:~<!left:?rdigits
& (!left*1/10:/|!right*1/10:/)
& ( @( !numpart
: ?
( #%@?digit ?
& @(!rdigits:?head !digit ?tail)
& str$(!head !tail):?rdigits
& ~
)
)
| !rdigits:&(!left,!right)
)
)
)
& R$(!len.0.!N.1 2 3 4 5 6 7 8 9)
: (
| ?fangsList
& out$(!N !fangsList)
& 1+!count:?count
)
)
& 0:?count
& 10:?i
& 16758243290880 24959017348650 14593825548650:?bignums
& whl
' ( ( vampire$!i&1+!i:?i
| !i*10:?i
)
& (!count:<25|!bignums:%?i ?bignums)
)
); |
http://rosettacode.org/wiki/Vampire_number | Vampire number | A vampire number is a natural decimal number with an even number of digits, that can be factored into two integers.
These two factors are called the fangs, and must have the following properties:
they each contain half the number of the decimal digits of the original number
together they consist of exactly the same decimal digits as the original number
at most one of them has a trailing zero
An example of a vampire number and its fangs: 1260 : (21, 60)
Task
Print the first 25 vampire numbers and their fangs.
Check if the following numbers are vampire numbers and, if so, print them and their fangs:
16758243290880, 24959017348650, 14593825548650
Note that a vampire number can have more than one pair of fangs.
See also
numberphile.com.
vampire search algorithm
vampire numbers on OEIS
| #C | C | #include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <math.h>
typedef uint64_t xint;
typedef unsigned long long ull;
xint tens[20];
inline xint max(xint a, xint b) { return a > b ? a : b; }
inline xint min(xint a, xint b) { return a < b ? a : b; }
inline int ndigits(xint x)
{
int n = 0;
while (x) n++, x /= 10;
return n;
}
inline xint dtally(xint x)
{
xint t = 0;
while (x) t += 1<<((x%10) * 6), x /= 10;
return t;
}
int fangs(xint x, xint *f)
{
int n = 0;
int nd = ndigits(x);
if (nd & 1) return 0;
nd /= 2;
xint lo, hi;
lo = max(tens[nd-1], (x + tens[nd] - 2)/ (tens[nd] - 1));
hi = min(x / lo, sqrt(x));
xint a, b, t = dtally(x);
for (a = lo; a <= hi; a++) {
b = x / a;
if (a * b == x && ((a%10) || (b%10)) && t == dtally(a) + dtally(b))
f[n++] = a;
}
return n;
}
void show_fangs(xint x, xint *f, xint cnt)
{
printf("%llu", (ull)x);
int i;
for (i = 0; i < cnt; i++)
printf(" = %llu x %llu", (ull)f[i], (ull)(x / f[i]));
putchar('\n');
}
int main(void)
{
int i, j, n;
xint x, f[16], bigs[] = {16758243290880ULL, 24959017348650ULL, 14593825548650ULL, 0};
tens[0] = 1;
for (i = 1; i < 20; i++)
tens[i] = tens[i-1] * 10;
for (x = 1, n = 0; n < 25; x++) {
if (!(j = fangs(x, f))) continue;
printf("%2d: ", ++n);
show_fangs(x, f, j);
}
putchar('\n');
for (i = 0; bigs[i]; i++) {
if ((j = fangs(bigs[i], f)))
show_fangs(bigs[i], f, j);
else
printf("%llu is not vampiric\n", (ull)bigs[i]);
}
return 0;
} |
http://rosettacode.org/wiki/Variable-length_quantity | Variable-length quantity | Implement some operations on variable-length quantities, at least including conversions from a normal number in the language to the binary representation of the variable-length quantity for that number, and vice versa. Any variants are acceptable.
Task
With above operations,
convert these two numbers 0x200000 (2097152 in decimal) and 0x1fffff (2097151 in decimal) into sequences of octets (an eight-bit byte);
display these sequences of octets;
convert these sequences of octets back to numbers, and check that they are equal to original numbers.
| #PARI.2FGP | PARI/GP | hex(s)=my(a=10,b=11,c=12,d=13,e=14,f=15);subst(Pol(eval(Vec(s))),'x,16);
n1=hex("200000");n2=hex("1fffff");
v1=digits(n1,256)
v2=digits(n2,256)
subst(Pol(v1),'x,256)==n1
subst(Pol(v2),'x,256)==n2 |
http://rosettacode.org/wiki/Variable-length_quantity | Variable-length quantity | Implement some operations on variable-length quantities, at least including conversions from a normal number in the language to the binary representation of the variable-length quantity for that number, and vice versa. Any variants are acceptable.
Task
With above operations,
convert these two numbers 0x200000 (2097152 in decimal) and 0x1fffff (2097151 in decimal) into sequences of octets (an eight-bit byte);
display these sequences of octets;
convert these sequences of octets back to numbers, and check that they are equal to original numbers.
| #Perl | Perl |
use warnings;
use strict;
for my $testcase (
0, 0xa, 123, 254, 255, 256,
257, 65534, 65535, 65536, 65537, 0x1fffff,
0x200000
)
{
my @vlq = vlq_encode($testcase);
printf "%8s %12s %8s\n", $testcase, ( join ':', @vlq ), vlq_decode(@vlq);
}
sub vlq_encode {
my @vlq;
my $binary = sprintf "%s%b", 0 x 7, shift;
$binary =~ s/(.{7})$//;
@vlq = ( unpack 'H2', ( pack 'B8', '0' . $1 ) );
while ( 0 + $binary ) {
$binary =~ s/(.{7})$//;
unshift @vlq, ( unpack 'H2', pack 'B8', '1' . $1 );
}
return @vlq;
}
sub vlq_decode {
my $num;
$num .= sprintf "%07b", hex(shift @_) & 0x7f while @_;
return oct '0b' . $num;
}
|
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function
| #D | D | import std.stdio, std.algorithm;
void printAll(TyArgs...)(TyArgs args) {
foreach (el; args)
el.writeln;
}
// Typesafe variadic function for dynamic array
void showSum1(int[] items...) {
items.sum.writeln;
}
// Typesafe variadic function for fixed size array
void showSum2(int[4] items...) {
items[].sum.writeln;
}
void main() {
printAll(4, 5.6, "Rosetta", "Code", "is", "awesome");
writeln;
showSum1(1, 3, 50);
showSum2(1, 3, 50, 10);
} |
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function
| #Delphi | Delphi | func printAll(args...) {
for i in args {
print(i)
}
}
printAll("test", "rosetta code", 123, 5.6) |
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Factor | Factor | USING: layouts memory prettyprint ;
! Show size in bytes
{ 1 2 3 } size . ! 48
1231298302914891021239102 size . ! 48
! Doesn't work on fixnums and other immediate objects
10 size . ! 0
! Show number of bits in a fixnum
fixnum-bits . ! 60 |
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Forth | Forth | : .CELLSIZE ( -- ) CR 1 CELLS . ." Bytes" ;
VARIABLE X ( creates a variable 1 cell wide) |
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Fortran | Fortran | INTEGER, PARAMETER :: i8 = SELECTED_INT_KIND(2)
INTEGER, PARAMETER :: i16 = SELECTED_INT_KIND(4)
INTEGER, PARAMETER :: i32 = SELECTED_INT_KIND(8)
INTEGER, PARAMETER :: i64 = SELECTED_INT_KIND(16)
INTEGER(i8) :: onebyte = 0
INTEGER(i16) :: twobytes = 0
INTEGER(i32) :: fourbytes = 0
INTEGER(i64) :: eightbytes = 0
WRITE (*,*) BIT_SIZE(onebyte), DIGITS(onebyte) ! prints 8 and 7
WRITE (*,*) BIT_SIZE(twobytes), DIGITS(twobytes) ! prints 16 and 15
WRITE (*,*) BIT_SIZE(fourbytes), DIGITS(fourbytes) ! prints 32 and 31
WRITE (*,*) BIT_SIZE(eightbytes), DIGITS(eightbytes) ! prints 64 and 63
WRITE (*,*) DIGITS(0.0), DIGITS(0d0) ! prints 24 and 53 |
http://rosettacode.org/wiki/Vector | Vector | Task
Implement a Vector class (or a set of functions) that models a Physical Vector. The four basic operations and a pretty print function should be implemented.
The Vector may be initialized in any reasonable way.
Start and end points, and direction
Angular coefficient and value (length)
The four operations to be implemented are:
Vector + Vector addition
Vector - Vector subtraction
Vector * scalar multiplication
Vector / scalar division
| #jq | jq | def polar(r; angle):
[ r*(angle|cos), r*(angle|sin) ];
# If your jq allows multi-arity functions, you may wish to uncomment the following line:
# def polar(r): [r, 0];
def polar2vector: polar(.[0]; .[1]);
def vector(x; y):
if (x|type) == "number" and (y|type) == "number" then [x,y]
else error("TypeError")
end;
# Input: an array of same-dimensional vectors of any dimension to be added
def sum:
def sum2: .[0] as $a | .[1] as $b | reduce range(0;$a|length) as $i ($a; .[$i] += $b[$i]);
if length <= 1 then .
else reduce .[1:][] as $v (.[0] ; [., $v]|sum2)
end;
def multiply(scalar): [ .[] * scalar ];
def negate: multiply(-1);
def minus(v): [., (v|negate)] | sum;
def divide(scalar):
if scalar == 0 then error("division of a vector by 0 is not supported")
else [ .[] / scalar ]
end;
def r: (.[0] | .*.) + (.[1] | .*.) | sqrt;
def atan2:
def pi: 1 | atan * 4;
def sign: if . < 0 then -1 elif . > 0 then 1 else 0 end;
.[0] as $x | .[1] as $y
| if $x == 0 then $y | sign * pi / 2
else ($y / $x) | if $x > 0 then atan elif . > 0 then atan - pi else atan + pi end
end;
def angle: atan2;
def topolar: [r, angle]; |
http://rosettacode.org/wiki/Vector | Vector | Task
Implement a Vector class (or a set of functions) that models a Physical Vector. The four basic operations and a pretty print function should be implemented.
The Vector may be initialized in any reasonable way.
Start and end points, and direction
Angular coefficient and value (length)
The four operations to be implemented are:
Vector + Vector addition
Vector - Vector subtraction
Vector * scalar multiplication
Vector / scalar division
| #Julia | Julia | module SpatialVectors
export SpatialVector
struct SpatialVector{N, T}
coord::NTuple{N, T}
end
SpatialVector(s::NTuple{N,T}, e::NTuple{N,T}) where {N,T} =
SpatialVector{N, T}(e .- s)
function SpatialVector(∠::T, val::T) where T
θ = atan(∠)
x = val * cos(θ)
y = val * sin(θ)
return SpatialVector((x, y))
end
angularcoef(v::SpatialVector{2, T}) where T = v.coord[2] / v.coord[1]
Base.norm(v::SpatialVector) = sqrt(sum(x -> x^2, v.coord))
function Base.show(io::IO, v::SpatialVector{2, T}) where T
∠ = angularcoef(v)
val = norm(v)
println(io, """2-dim spatial vector
- Angular coef ∠: $(∠) (θ = $(rad2deg(atan(∠)))°)
- Magnitude: $(val)
- X coord: $(v.coord[1])
- Y coord: $(v.coord[2])""")
end
Base.:-(v::SpatialVector) = SpatialVector(.- v.coord)
for op in (:+, :-)
@eval begin
Base.$op(a::SpatialVector{N, T}, b::SpatialVector{N, U}) where {N, T, U} =
SpatialVector{N, promote_type(T, U)}(broadcast($op, a.coord, b.coord))
end
end
for op in (:*, :/)
@eval begin
Base.$op(n::T, v::SpatialVector{N, U}) where {N, T, U} =
SpatialVector{N, promote_type(T, U)}(broadcast($op, n, v.coord))
Base.$op(v::SpatialVector, n::Number) = $op(n, v)
end
end
end # module Vectors |
http://rosettacode.org/wiki/Verify_distribution_uniformity/Chi-squared_test | Verify distribution uniformity/Chi-squared test | Task
Write a function to verify that a given distribution of values is uniform by using the
χ
2
{\displaystyle \chi ^{2}}
test to see if the distribution has a likelihood of happening of at least the significance level (conventionally 5%).
The function should return a boolean that is true if the distribution is one that a uniform distribution (with appropriate number of degrees of freedom) may be expected to produce.
Reference
an entry at the MathWorld website: chi-squared distribution.
| #Tcl | Tcl | package require Tcl 8.5
package require math::statistics
proc isUniform {distribution {significance 0.05}} {
set count [tcl::mathop::+ {*}[dict values $distribution]]
set expected [expr {double($count) / [dict size $distribution]}]
set X2 0.0
foreach value [dict values $distribution] {
set X2 [expr {$X2 + ($value - $expected)**2 / $expected}]
}
set degreesOfFreedom [expr {[dict size $distribution] - 1}]
set likelihoodOfRandom [::math::statistics::incompleteGamma \
[expr {$degreesOfFreedom / 2.0}] [expr {$X2 / 2.0}]]
expr {$likelihoodOfRandom > $significance}
} |
http://rosettacode.org/wiki/Vigen%C3%A8re_cipher | Vigenère cipher | Task
Implement a Vigenère cypher, both encryption and decryption.
The program should handle keys and text of unequal length,
and should capitalize everything and discard non-alphabetic characters.
(If your program handles non-alphabetic characters in another way,
make a note of it.)
Related tasks
Caesar cipher
Rot-13
Substitution Cipher
| #Lua | Lua | function Encrypt( _msg, _key )
local msg = { _msg:upper():byte( 1, -1 ) }
local key = { _key:upper():byte( 1, -1 ) }
local enc = {}
local j, k = 1, 1
for i = 1, #msg do
if msg[i] >= string.byte('A') and msg[i] <= string.byte('Z') then
enc[k] = ( msg[i] + key[j] - 2*string.byte('A') ) % 26 + string.byte('A')
k = k + 1
if j == #key then j = 1 else j = j + 1 end
end
end
return string.char( unpack(enc) )
end
function Decrypt( _msg, _key )
local msg = { _msg:byte( 1, -1 ) }
local key = { _key:upper():byte( 1, -1 ) }
local dec = {}
local j = 1
for i = 1, #msg do
dec[i] = ( msg[i] - key[j] + 26 ) % 26 + string.byte('A')
if j == #key then j = 1 else j = j + 1 end
end
return string.char( unpack(dec) )
end
original = "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!"
key = "VIGENERECIPHER";
encrypted = Encrypt( original, key )
decrypted = Decrypt( encrypted, key )
print( encrypted )
print( decrypted ) |
http://rosettacode.org/wiki/Visualize_a_tree | Visualize a tree | A tree structure (i.e. a rooted, connected acyclic graph) is often used in programming.
It's often helpful to visually examine such a structure.
There are many ways to represent trees to a reader, such as:
indented text (à la unix tree command)
nested HTML tables
hierarchical GUI widgets
2D or 3D images
etc.
Task
Write a program to produce a visual representation of some tree.
The content of the tree doesn't matter, nor does the output format, the only requirement being that the output is human friendly.
Make do with the vague term "friendly" the best you can.
| #Ruby | Ruby |
root = BinaryTreeNode.from_array [1, [2, [4, 7], [5]], [3, [6, [8], [9]]]]
|
http://rosettacode.org/wiki/Visualize_a_tree | Visualize a tree | A tree structure (i.e. a rooted, connected acyclic graph) is often used in programming.
It's often helpful to visually examine such a structure.
There are many ways to represent trees to a reader, such as:
indented text (à la unix tree command)
nested HTML tables
hierarchical GUI widgets
2D or 3D images
etc.
Task
Write a program to produce a visual representation of some tree.
The content of the tree doesn't matter, nor does the output format, the only requirement being that the output is human friendly.
Make do with the vague term "friendly" the best you can.
| #Rust | Rust |
extern crate rustc_serialize;
extern crate term_painter;
use rustc_serialize::json;
use std::fmt::{Debug, Display, Formatter, Result};
use term_painter::ToStyle;
use term_painter::Color::*;
type NodePtr = Option<usize>;
#[derive(Debug, PartialEq, Clone, Copy)]
enum Side {
Left,
Right,
Up,
}
#[derive(Debug, PartialEq, Clone, Copy)]
enum DisplayElement {
TrunkSpace,
SpaceLeft,
SpaceRight,
SpaceSpace,
Root,
}
impl DisplayElement {
fn string(&self) -> String {
match *self {
DisplayElement::TrunkSpace => " │ ".to_string(),
DisplayElement::SpaceRight => " ┌───".to_string(),
DisplayElement::SpaceLeft => " └───".to_string(),
DisplayElement::SpaceSpace => " ".to_string(),
DisplayElement::Root => "├──".to_string(),
}
}
}
#[derive(Debug, Clone, Copy, RustcDecodable, RustcEncodable)]
struct Node<K, V> {
key: K,
value: V,
left: NodePtr,
right: NodePtr,
up: NodePtr,
}
impl<K: Ord + Copy, V: Copy> Node<K, V> {
pub fn get_ptr(&self, side: Side) -> NodePtr {
match side {
Side::Up => self.up,
Side::Left => self.left,
_ => self.right,
}
}
}
#[derive(Debug, RustcDecodable, RustcEncodable)]
struct Tree<K, V> {
root: NodePtr,
store: Vec<Node<K, V>>,
}
impl<K: Ord + Copy + Debug + Display, V: Debug + Copy + Display> Tree<K, V> {
pub fn get_node(&self, np: NodePtr) -> Node<K, V> {
assert!(np.is_some());
self.store[np.unwrap()]
}
pub fn get_pointer(&self, np: NodePtr, side: Side) -> NodePtr {
assert!(np.is_some());
self.store[np.unwrap()].get_ptr(side)
}
// Prints the tree with root p. The idea is to do an in-order traversal
// (reverse in-order in this case, where right is on top), and print nodes as they
// are visited, one per line. Each invocation of display() gets its own copy
// of the display element vector e, which is grown with either whitespace or
// a trunk element, then modified in its last and possibly second-to-last
// characters in context.
fn display(&self, p: NodePtr, side: Side, e: &Vec<DisplayElement>, f: &mut Formatter) {
if p.is_none() {
return;
}
let mut elems = e.clone();
let node = self.get_node(p);
let mut tail = DisplayElement::SpaceSpace;
if node.up != self.root {
// If the direction is switching, I need the trunk element to appear in the lines
// printed before that node is visited.
if side == Side::Left && node.right.is_some() {
elems.push(DisplayElement::TrunkSpace);
} else {
elems.push(DisplayElement::SpaceSpace);
}
}
let hindex = elems.len() - 1;
self.display(node.right, Side::Right, &elems, f);
if p == self.root {
elems[hindex] = DisplayElement::Root;
tail = DisplayElement::TrunkSpace;
} else if side == Side::Right {
// Right subtree finished
elems[hindex] = DisplayElement::SpaceRight;
// Prepare trunk element in case there is a left subtree
tail = DisplayElement::TrunkSpace;
} else if side == Side::Left {
elems[hindex] = DisplayElement::SpaceLeft;
let parent = self.get_node(node.up);
if parent.up.is_some() && self.get_pointer(parent.up, Side::Right) == node.up {
// Direction switched, need trunk element starting with this node/line
elems[hindex - 1] = DisplayElement::TrunkSpace;
}
}
// Visit node => print accumulated elements. Each node gets a line and each line gets a
// node.
for e in elems.clone() {
let _ = write!(f, "{}", e.string());
}
let _ = write!(f,
"{key:>width$} ",
key = Green.bold().paint(node.key),
width = 2);
let _ = write!(f,
"{value:>width$}\n",
value = Blue.bold().paint(format!("{:.*}", 2, node.value)),
width = 4);
// Overwrite last element before continuing traversal
elems[hindex] = tail;
self.display(node.left, Side::Left, &elems, f);
}
}
impl<K: Ord + Copy + Debug + Display, V: Debug + Copy + Display> Display for Tree<K, V> {
fn fmt(&self, f: &mut Formatter) -> Result {
if self.root.is_none() {
write!(f, "[empty]")
} else {
let mut v: Vec<DisplayElement> = Vec::new();
self.display(self.root, Side::Up, &mut v, f);
Ok(())
}
}
}
/// Decodes and prints a previously generated tree.
fn main() {
let encoded = r#"{"root":0,"store":[{"key":0,"value":0.45,"left":1,"right":3,
"up":null},{"key":-8,"value":-0.94,"left":7,"right":2,"up":0}, {"key":-1,
"value":0.15,"left":8,"right":null,"up":1},{"key":7, "value":-0.29,"left":4,
"right":9,"up":0},{"key":5,"value":0.80,"left":5,"right":null,"up":3},
{"key":4,"value":-0.85,"left":6,"right":null,"up":4},{"key":3,"value":-0.46,
"left":null,"right":null,"up":5},{"key":-10,"value":-0.85,"left":null,
"right":13,"up":1},{"key":-6,"value":-0.42,"left":null,"right":10,"up":2},
{"key":9,"value":0.63,"left":12,"right":null,"up":3},{"key":-3,"value":-0.83,
"left":null,"right":11,"up":8},{"key":-2,"value":0.75,"left":null,"right":null,
"up":10},{"key":8,"value":-0.48,"left":null,"right":null,"up":9},{"key":-9,
"value":0.53,"left":null,"right":null,"up":7}]}"#;
let tree: Tree<i32, f32> = json::decode(&encoded).unwrap();
println!("{}", tree);
}
|
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively (read a single directory).
| #Prolog_2 | Prolog | % submitted by Aykayayciti (Earl Lamont Montgomery)
% altered from fsaenzperez April 2019
% (swi-prolog.discourse-group)
test_run :-
proc_dir('C:\\vvvv\\vvvv_beta_39_x64').
proc_dir(Directory) :-
format('Directory: ~w~n',[Directory]),
directory_files(Directory,Files),!, %cut inserted
proc_files(Directory,Files).
proc_files(Directory, [File|Files]) :-
proc_file(Directory, File),!, %cut inserted
proc_files(Directory, Files).
proc_files(_Directory, []).
proc_file(Directory, File) :-
(
File = '.',
directory_file_path(Directory, File, Path),
exists_directory(Path),!,%cut inserted
format('Directory: ~w~n',[File])
;
File = '..',
directory_file_path(Directory, File, Path),
exists_directory(Path),!,%cut inserted
format('Directory: ~w~n',[File])
;
directory_file_path(Directory, File, Path),
exists_directory(Path),!,%cut inserted
proc_dir(Path)
;
directory_file_path(Directory, File, Path),
exists_file(Path),!,%cut inserted
format('File: ~w~n',[File])
;
format('Unknown: ~w~n',[File])
). |
http://rosettacode.org/wiki/Water_collected_between_towers | Water collected between towers | Task
In a two-dimensional world, we begin with any bar-chart (or row of close-packed 'towers', each of unit width), and then it rains,
completely filling all convex enclosures in the chart with water.
9 ██ 9 ██
8 ██ 8 ██
7 ██ ██ 7 ██≈≈≈≈≈≈≈≈██
6 ██ ██ ██ 6 ██≈≈██≈≈≈≈██
5 ██ ██ ██ ████ 5 ██≈≈██≈≈██≈≈████
4 ██ ██ ████████ 4 ██≈≈██≈≈████████
3 ██████ ████████ 3 ██████≈≈████████
2 ████████████████ ██ 2 ████████████████≈≈██
1 ████████████████████ 1 ████████████████████
In the example above, a bar chart representing the values [5, 3, 7, 2, 6, 4, 5, 9, 1, 2] has filled, collecting 14 units of water.
Write a function, in your language, from a given array of heights, to the number of water units that can be held in this way, by a corresponding bar chart.
Calculate the number of water units that could be collected by bar charts representing each of the following seven series:
[[1, 5, 3, 7, 2],
[5, 3, 7, 2, 6, 4, 5, 9, 1, 2],
[2, 6, 3, 5, 2, 8, 1, 4, 2, 2, 5, 3, 5, 7, 4, 1],
[5, 5, 5, 5],
[5, 6, 7, 8],
[8, 7, 7, 6],
[6, 7, 10, 7, 6]]
See, also:
Four Solutions to a Trivial Problem – a Google Tech Talk by Guy Steele
Water collected between towers on Stack Overflow, from which the example above is taken)
An interesting Haskell solution, using the Tardis monad, by Phil Freeman in a Github gist.
| #Rust | Rust |
use std::cmp::min;
fn getfill(pattern: &[usize]) -> usize {
let mut total = 0;
for (idx, val) in pattern.iter().enumerate() {
let l_peak = pattern[..idx].iter().max();
let r_peak = pattern[idx + 1..].iter().max();
if l_peak.is_some() && r_peak.is_some() {
let peak = min(l_peak.unwrap(), r_peak.unwrap());
if peak > val {
total += peak - val;
}
}
}
total
}
fn main() {
let patterns = vec![
vec![1, 5, 3, 7, 2],
vec![5, 3, 7, 2, 6, 4, 5, 9, 1, 2],
vec![2, 6, 3, 5, 2, 8, 1, 4, 2, 2, 5, 3, 5, 7, 4, 1],
vec![5, 5, 5, 5],
vec![5, 6, 7, 8],
vec![8, 7, 7, 6],
vec![6, 7, 10, 7, 6],
];
for pattern in patterns {
println!("pattern: {:?}, fill: {}", &pattern, getfill(&pattern));
}
}
|
http://rosettacode.org/wiki/Vector_products | Vector products | A vector is defined as having three dimensions as being represented by an ordered collection of three numbers: (X, Y, Z).
If you imagine a graph with the x and y axis being at right angles to each other and having a third, z axis coming out of the page, then a triplet of numbers, (X, Y, Z) would represent a point in the region, and a vector from the origin to the point.
Given the vectors:
A = (a1, a2, a3)
B = (b1, b2, b3)
C = (c1, c2, c3)
then the following common vector products are defined:
The dot product (a scalar quantity)
A • B = a1b1 + a2b2 + a3b3
The cross product (a vector quantity)
A x B = (a2b3 - a3b2, a3b1 - a1b3, a1b2 - a2b1)
The scalar triple product (a scalar quantity)
A • (B x C)
The vector triple product (a vector quantity)
A x (B x C)
Task
Given the three vectors:
a = ( 3, 4, 5)
b = ( 4, 3, 5)
c = (-5, -12, -13)
Create a named function/subroutine/method to compute the dot product of two vectors.
Create a function to compute the cross product of two vectors.
Optionally create a function to compute the scalar triple product of three vectors.
Optionally create a function to compute the vector triple product of three vectors.
Compute and display: a • b
Compute and display: a x b
Compute and display: a • (b x c), the scalar triple product.
Compute and display: a x (b x c), the vector triple product.
References
A starting page on Wolfram MathWorld is Vector Multiplication .
Wikipedia dot product.
Wikipedia cross product.
Wikipedia triple product.
Related tasks
Dot product
Quaternion type
| #AWK | AWK | #!/usr/bin/awk -f
BEGIN {
a[1] = 3; a[2]= 4; a[3] = 5;
b[1] = 4; b[2]= 3; b[3] = 5;
c[1] = -5; c[2]= -12; c[3] = -13;
print "a = ",printVec(a);
print "b = ",printVec(b);
print "c = ",printVec(c);
print "a.b = ",dot(a,b);
## upper case variables are used as temporary or intermediate results
cross(a,b,D);print "a.b = ",printVec(D);
cross(b,c,D);print "a.(b x c) = ",dot(a,D);
cross(b,c,D);cross(a,D,E); print "a x (b x c) = ",printVec(E);
}
function dot(A,B) {
return A[1]*B[1]+A[2]*B[2]+A[3]*B[3];
}
function cross(A,B,C) {
C[1] = A[2]*B[3]-A[3]*B[2];
C[2] = A[3]*B[1]-A[1]*B[3];
C[3] = A[1]*B[2]-A[2]*B[1];
}
function printVec(C) {
return "[ "C[1]" "C[2]" "C[3]" ]";
} |
http://rosettacode.org/wiki/Validate_International_Securities_Identification_Number | Validate International Securities Identification Number | An International Securities Identification Number (ISIN) is a unique international identifier for a financial security such as a stock or bond.
Task
Write a function or program that takes a string as input, and checks whether it is a valid ISIN.
It is only valid if it has the correct format, and the embedded checksum is correct.
Demonstrate that your code passes the test-cases listed below.
Details
The format of an ISIN is as follows:
┌───────────── a 2-character ISO country code (A-Z)
│ ┌─────────── a 9-character security code (A-Z, 0-9)
│ │ ┌── a checksum digit (0-9)
AU0000XVGZA3
For this task, you may assume that any 2-character alphabetic sequence is a valid country code.
The checksum can be validated as follows:
Replace letters with digits, by converting each character from base 36 to base 10, e.g. AU0000XVGZA3 →1030000033311635103.
Perform the Luhn test on this base-10 number.
There is a separate task for this test: Luhn test of credit card numbers.
You don't have to replicate the implementation of this test here ─── you can just call the existing function from that task. (Add a comment stating if you did this.)
Test cases
ISIN
Validity
Comment
US0378331005
valid
US0373831005
not valid
The transposition typo is caught by the checksum constraint.
U50378331005
not valid
The substitution typo is caught by the format constraint.
US03378331005
not valid
The duplication typo is caught by the format constraint.
AU0000XVGZA3
valid
AU0000VXGZA3
valid
Unfortunately, not all transposition typos are caught by the checksum constraint.
FR0000988040
valid
(The comments are just informational. Your function should simply return a Boolean result. See #Raku for a reference solution.)
Related task:
Luhn test of credit card numbers
Also see
Interactive online ISIN validator
Wikipedia article: International Securities Identification Number
| #360_Assembly | 360 Assembly | * Validate ISIN 08/03/2019
VALISIN CSECT
USING VALISIN,R13 base register
B 72(R15) skip savearea
DC 17F'0' savearea
SAVE (14,12) save previous context
ST R13,4(R15) link backward
ST R15,8(R13) link forward
LR R13,R15 set addressability
LA R7,1 j=1
DO WHILE=(C,R7,LE,=A(NN)) do j=1 to hbound(tt)
LR R1,R7 j
SLA R1,4 ~
LA R4,TT-16(R1) @tt(j)
MVC CC,0(R4) cc=tt(j)
MVC C,=CL28' ' c=' '
MVC R,=CL28' ' r=' '
MVI ERR,X'00' err=false
MVC LCC,=F'0' lcc=0
LA R1,L'CC i=length(cc)
LENTRIA LA R5,CC-1 @cc
AR R5,R1 +i
CLI 0(R5),C' ' if cc[i]=' '
BE LENTRIB then iterate loop
ST R1,LCC lcc=lentrim(cc)
B LENTRIC leave loop
LENTRIB BCT R1,LENTRIA i--; if i<>0 then loop
LENTRIC L R4,LCC lcc
IF CH,R4,EQ,=H'12' THEN if lcc=12 then
MVC LC,=F'0' lc=0
MVC WW,=CL28' ' ww=''
LA R10,WW @ww
LA R6,1 i=1
DO WHILE=(C,R6,LE,LCC) do i=1 to lcc
LA R4,CC-1 @cc
AR R4,R6 +i
MVC CI(1),0(R4) ci=substr(cc,i,1)
LA R2,BASE36 @base36
LA R3,L'BASE36 length(base36)
BAL R14,INDEX r0=index(base36,ci)
IF LTR,R0,NZ,R0 THEN if p<>0 then
LR R1,R0 ip
BCTR R1,0 -1
XDECO R1,XDEC str(ip-1)
MVC 0(2,R10),XDEC+10 ww=ww||str(p-1)
ELSE , else
MVI ERR,X'FF' err=true
ENDIF , endif
LA R10,2(R10) @ww+=2
LA R6,1(R6) i++
ENDDO , enddo i
MVC C,=CL28' ' c=''
LA R8,WW @ww
LA R9,C @c
LA R10,0 length(c)
LA R6,1 i=1
DO WHILE=(C,R6,LE,=A(L'WW)) do i=1 to length(ww)
IF CLI,0(R8),NE,C' ' THEN if ww[i]<>' ' then
MVC 0(1,R9),0(R8) c=ww[i]
LA R9,1(R9) @c++
LA R10,1(R10) length(c)++
ENDIF , endif
LA R8,1(R8) @ww++
LA R6,1(R6) i++
ENDDO , enddo i
ST R10,LC lc=length(c)
LA R6,1 i=1
DO WHILE=(CH,R6,LE,=H'2') do i=1 to 2
LA R4,CC-1 @cc
AR R4,R6 +i
MVC CI(1),0(R4) ci=substr(cc,i,1)
LA R2,ALPHA @alpha
LA R3,L'ALPHA length(alpha)
BAL R14,INDEX r0=index(alpha,ci)
IF LTR,R0,Z,R0 THEN if index(alpha,ci)=0 then
MVI ERR,X'FF' err=true
ENDIF , endif
LA R6,1(R6) i++
ENDDO , enddo i
SR R8,R8 i1=0
SR R9,R9 i2=0
IF CLI,ERR,EQ,X'00' THEN if not err then
SR R0,R0 0
L R6,LC i=lc
MVC R,=CL28' ' r=''
LA R10,C @c
LA R11,R-1 @r
A R11,LC @r=@r+length(strip((c))
DO WHILE=(CH,R6,GE,=H'1') do i=lc to 1 step -1
MVC 0(1,R11),0(R10) r[k]=c[i]
BCTR R11,0 @r--
LA R10,1(R10) @c++
BCTR R6,0 i--
ENDDO , enddo i
LA R6,1 i=1
DO WHILE=(C,R6,LE,LC) do i=1 to lc step 2
LA R4,R-1 @r
AR R4,R6 +i
MVC CI(1),0(R4) ci=substr(r,i,1)
MVC XDEC,=CL12' ' ~
MVC XDEC(L'CI),CI ci
XDECI R2,XDEC int(ci)
AR R8,R2 i1=i1+int(ci)
LA R6,2(R6) i+=2
ENDDO , enddo i
LA R6,2 i=2
DO WHILE=(C,R6,LE,LC) do i=2 to lc step 2
LA R4,R-1 @r
AR R4,R6 +i
MVC CI(1),0(R4) ci=substr(r,i,1)
MVC XDEC,=CL12' ' ~
MVC XDEC(L'CI),CI ci
XDECI R10,XDEC int(ci)
SLA R10,1 ii=int(ci)*2
IF CH,R10,GE,=H'10' THEN if ii>=10 then
SH R10,=H'9' ii=ii-9
ENDIF , endif
AR R9,R10 i2=i2+ii
LA R6,2(R6) i++
ENDDO , enddo i
LR R2,R8 i1
AR R2,R9 +i2
XDECO R2,XDEC s=str(i1+i2)
IF CLI,XDEC+11,EQ,C'0' THEN if substr(s,length(s),1)='0' then
MVC MSG,=CL6'OK' msg='ok'
ELSE , else
MVC MSG,=CL6'?err1' msg='?1'
ENDIF , endif
ELSE , else
MVC MSG,=CL6'?err2' msg='?2'
ENDIF , endif
ELSE , else
MVC MSG,=CL6'?err3' msg='?3'
ENDIF , endif
XDECO R7,XDEC edit j
MVC PG(2),XDEC+10 j
MVC PG+3(16),CC cc
MVC PG+20(6),MSG msg
XPRNT PG,L'PG print buffer
LA R7,1(R7) j++
ENDDO , enddo j
L R13,4(0,R13) restore previous savearea pointer
RETURN (14,12),RC=0 restore registers from calling sav
MVCX MVC 0(0,R4),0(R5) pattern svc
INDEX SR R0,R0 index(r2,ci) r3=len
LA R1,1 k=1
SINDEXA CR R1,R3 do k=1 to length(ca)
BH SINDEXC ~
CLC 0(1,R2),CI if ca[k]=ci
BNE SINDEXB then iterate loop
LR R0,R1 ii=k
B SINDEXC exit loop
SINDEXB LA R2,1(R2) @ca++
LA R1,1(R1) k++
B SINDEXA enddo
SINDEXC BR R14 end index
NN EQU (BASE36-TT)/16 number of items
TT DC CL16'US0378331005',CL16'US0373831005'
DC CL16'U50378331005',CL16'US03378331005'
DC CL16'AU0000XVGZA3',CL16'AU0000VXGZA3'
DC CL16'FR0000988040'
BASE36 DC CL36'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
ALPHA DC CL26'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
ERR DS X error
LCC DS F length of cc
LC DS F length of c
CI DS CL1
CC DS CL16 current element of tt
C DS CL28
R DS CL28
WW DS CL28
MSG DS CL6 message
PG DC CL80' ' buffer
XDEC DS CL12 temp for xdeco and xdeci
REGEQU
END VALISIN |
http://rosettacode.org/wiki/Validate_International_Securities_Identification_Number | Validate International Securities Identification Number | An International Securities Identification Number (ISIN) is a unique international identifier for a financial security such as a stock or bond.
Task
Write a function or program that takes a string as input, and checks whether it is a valid ISIN.
It is only valid if it has the correct format, and the embedded checksum is correct.
Demonstrate that your code passes the test-cases listed below.
Details
The format of an ISIN is as follows:
┌───────────── a 2-character ISO country code (A-Z)
│ ┌─────────── a 9-character security code (A-Z, 0-9)
│ │ ┌── a checksum digit (0-9)
AU0000XVGZA3
For this task, you may assume that any 2-character alphabetic sequence is a valid country code.
The checksum can be validated as follows:
Replace letters with digits, by converting each character from base 36 to base 10, e.g. AU0000XVGZA3 →1030000033311635103.
Perform the Luhn test on this base-10 number.
There is a separate task for this test: Luhn test of credit card numbers.
You don't have to replicate the implementation of this test here ─── you can just call the existing function from that task. (Add a comment stating if you did this.)
Test cases
ISIN
Validity
Comment
US0378331005
valid
US0373831005
not valid
The transposition typo is caught by the checksum constraint.
U50378331005
not valid
The substitution typo is caught by the format constraint.
US03378331005
not valid
The duplication typo is caught by the format constraint.
AU0000XVGZA3
valid
AU0000VXGZA3
valid
Unfortunately, not all transposition typos are caught by the checksum constraint.
FR0000988040
valid
(The comments are just informational. Your function should simply return a Boolean result. See #Raku for a reference solution.)
Related task:
Luhn test of credit card numbers
Also see
Interactive online ISIN validator
Wikipedia article: International Securities Identification Number
| #Ada | Ada | procedure ISIN is
-- Luhn_Test copied from other Task
function Luhn_Test (Number: String) return Boolean is
Sum : Natural := 0;
Odd : Boolean := True;
Digit: Natural range 0 .. 9;
begin
for p in reverse Number'Range loop
Digit := Integer'Value (Number (p..p));
if Odd then
Sum := Sum + Digit;
else
Sum := Sum + (Digit*2 mod 10) + (Digit / 5);
end if;
Odd := not Odd;
end loop;
return (Sum mod 10) = 0;
end Luhn_Test;
subtype Decimal is Character range '0' .. '9';
subtype Letter is Character range 'A' .. 'Z';
subtype ISIN_Type is String(1..12);
-- converts a string of decimals and letters into a string of decimals
function To_Digits(S: String) return String is
-- Character'Pos('A')-Offset=10, Character'Pos('B')-Offset=11, ...
Offset: constant Integer := Character'Pos('A')-10;
Invalid_Character: exception;
begin
if S = "" then
return "";
elsif S(S'First) = ' ' then -- skip blanks
return To_Digits(S(S'First+1 .. S'Last));
elsif S(S'First) in Decimal then
return S(S'First) & To_Digits(S(S'First+1 .. S'Last));
elsif S(S'First) in Letter then
return To_Digits(Integer'Image(Character'Pos(S(S'First))-Offset))
& To_Digits(S(S'First+1 .. S'Last));
else
raise Invalid_Character;
end if;
end To_Digits;
function Is_Valid_ISIN(S: ISIN_Type) return Boolean is
Number : String := To_Digits(S);
begin
return S(S'First) in Letter and
S(S'First+1) in Letter and
S(S'Last) in Decimal and
Luhn_Test(Number);
end Is_Valid_ISIN;
Test_Cases : constant Array(1..6) of ISIN_Type :=
("US0378331005",
"US0373831005",
"U50378331005",
-- excluded by type with fixed length
-- "US03378331005",
"AU0000XVGZA3",
"AU0000VXGZA3",
"FR0000988040");
begin
for I in Test_Cases'Range loop
Ada.Text_IO.Put_Line(Test_Cases(I) & ":" &
Boolean'Image(Is_Valid_ISIN(Test_Cases(I))));
end loop;
-- using wrong length will result in an exception:
Ada.Text_IO.Put("US03378331005:");
Ada.Text_IO.Put_Line(Boolean'Image(Is_Valid_Isin("US03378331005")));
exception
when others =>
Ada.Text_IO.Put_Line("Exception occured");
end ISIN; |
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #jq | jq | [1,2,2,3,4,4,5]
| . as $array
| range(1;length)
| select( $array[.] == $array[.-1])
|
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #Julia | Julia |
s = [1, 2, 2, 3, 4, 4, 5]
for i in eachindex(s)
curr = s[i]
i > 1 && curr == prev && println(i)
prev = curr
end
|
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #Perl | Perl | @s = <1 2 2 3 4 4 5>;
for ($i = 0; $i < 7; $i++) {
$curr = $s[$i];
if ($i > 1 and $curr == $prev) { print "$i\n" }
$prev = $curr;
} |
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #Phix | Phix | with javascript_semantics
sequence s = {1,2,2,3,4,4,5}
for i=1 to length(s) do
integer curr = s[i], prev
if i>1 and curr=prev then
?i
end if
prev = curr
end for
|
http://rosettacode.org/wiki/Van_der_Corput_sequence | Van der Corput sequence | When counting integers in binary, if you put a (binary) point to the righEasyLangt of the count then the column immediately to the left denotes a digit with a multiplier of
2
0
{\displaystyle 2^{0}}
; the digit in the next column to the left has a multiplier of
2
1
{\displaystyle 2^{1}}
; and so on.
So in the following table:
0.
1.
10.
11.
...
the binary number "10" is
1
×
2
1
+
0
×
2
0
{\displaystyle 1\times 2^{1}+0\times 2^{0}}
.
You can also have binary digits to the right of the “point”, just as in the decimal number system. In that case, the digit in the place immediately to the right of the point has a weight of
2
−
1
{\displaystyle 2^{-1}}
, or
1
/
2
{\displaystyle 1/2}
.
The weight for the second column to the right of the point is
2
−
2
{\displaystyle 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
. And so on.
If you take the integer binary count of the first table, and reflect the digits about the binary point, you end up with the van der Corput sequence of numbers in base 2.
.0
.1
.01
.11
...
The third member of the sequence, binary 0.01, is therefore
0
×
2
−
1
+
1
×
2
−
2
{\displaystyle 0\times 2^{-1}+1\times 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
.
Distribution of 2500 points each: Van der Corput (top) vs pseudorandom
0
≤
x
<
1
{\displaystyle 0\leq x<1}
Monte Carlo simulations
This sequence is also a superset of the numbers representable by the "fraction" field of an old IEEE floating point standard. In that standard, the "fraction" field represented the fractional part of a binary number beginning with "1." e.g. 1.101001101.
Hint
A hint at a way to generate members of the sequence is to modify a routine used to change the base of an integer:
>>> def base10change(n, base):
digits = []
while n:
n,remainder = divmod(n, base)
digits.insert(0, remainder)
return digits
>>> base10change(11, 2)
[1, 0, 1, 1]
the above showing that 11 in decimal is
1
×
2
3
+
0
×
2
2
+
1
×
2
1
+
1
×
2
0
{\displaystyle 1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+1\times 2^{0}}
.
Reflected this would become .1101 or
1
×
2
−
1
+
1
×
2
−
2
+
0
×
2
−
3
+
1
×
2
−
4
{\displaystyle 1\times 2^{-1}+1\times 2^{-2}+0\times 2^{-3}+1\times 2^{-4}}
Task description
Create a function/method/routine that given n, generates the n'th term of the van der Corput sequence in base 2.
Use the function to compute and display the first ten members of the sequence. (The first member of the sequence is for n=0).
As a stretch goal/extra credit, compute and show members of the sequence for bases other than 2.
See also
The Basic Low Discrepancy Sequences
Non-decimal radices/Convert
Van der Corput sequence
| #ActionScript | ActionScript |
package {
import flash.display.Sprite;
import flash.events.Event;
public class VanDerCorput extends Sprite {
public function VanDerCorput():void {
if (stage) init();
else addEventListener(Event.ADDED_TO_STAGE, init);
}
private function init(e:Event = null):void {
removeEventListener(Event.ADDED_TO_STAGE, init);
var base2:Vector.<Number> = new Vector.<Number>(10, true);
var base3:Vector.<Number> = new Vector.<Number>(10, true);
var base4:Vector.<Number> = new Vector.<Number>(10, true);
var base5:Vector.<Number> = new Vector.<Number>(10, true);
var base6:Vector.<Number> = new Vector.<Number>(10, true);
var base7:Vector.<Number> = new Vector.<Number>(10, true);
var base8:Vector.<Number> = new Vector.<Number>(10, true);
var i:uint;
for ( i = 0; i < 10; i++ ) {
base2[i] = Math.round( _getTerm(i, 2) * 1000000 ) / 1000000;
base3[i] = Math.round( _getTerm(i, 3) * 1000000 ) / 1000000;
base4[i] = Math.round( _getTerm(i, 4) * 1000000 ) / 1000000;
base5[i] = Math.round( _getTerm(i, 5) * 1000000 ) / 1000000;
base6[i] = Math.round( _getTerm(i, 6) * 1000000 ) / 1000000;
base7[i] = Math.round( _getTerm(i, 7) * 1000000 ) / 1000000;
base8[i] = Math.round( _getTerm(i, 8) * 1000000 ) / 1000000;
}
trace("Base 2: " + base2.join(', '));
trace("Base 3: " + base3.join(', '));
trace("Base 4: " + base4.join(', '));
trace("Base 5: " + base5.join(', '));
trace("Base 6: " + base6.join(', '));
trace("Base 7: " + base7.join(', '));
trace("Base 8: " + base8.join(', '));
}
private function _getTerm(n:uint, base:uint = 2):Number {
var r:Number = 0, p:uint, digit:uint;
var baseLog:Number = Math.log(base);
while ( n > 0 ) {
p = Math.pow( base, uint(Math.log(n) / baseLog) );
digit = n / p;
n %= p;
r += digit / (p * base);
}
return r;
}
}
}
|
http://rosettacode.org/wiki/Variables | Variables | Task
Demonstrate a language's methods of:
variable declaration
initialization
assignment
datatypes
scope
referencing, and
other variable related facilities
| #AArch64_Assembly | AArch64 Assembly |
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program variable64.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
/*********************************/
/* Initialized data */
/*********************************/
.data
szString: .asciz "String définition"
sArea1: .fill 11, 1, ' ' // 11 spaces
// or
sArea2: .space 11,' ' // 11 spaces
cCharac: .byte '\n' // character
cByte1: .byte 0b10101 // 1 byte binary value
hHalfWord1: .hword 0xFF // 2 bytes value hexa
.align 4
iInteger1: .int 123456 // 4 bytes value decimal
iInteger3: .short 0500 // 4 bytes value octal
iInteger5: .int 0x4000 // 4 bytes value hexa
iInteger7: .word 0x4000 // 4 bytes value hexa
iInteger6: .int 04000 // 4 bytes value octal
TabInteger4: .int 5,4,3,2 // Area of 4 integers = 4 * 4 = 16 bytes
dDoubleInt1: .quad 0xFFFFFFFFFFFFFFFF // 8 bytes value hexa
dfFLOAT1: .double 0f-31415926535897932384626433832795028841971.693993751E-40 // Float 8 bytes
sfFLOAT2: .float 0f-31415926535897932384626433832795028841971.693993751E-40 // Float 4 bytes (or use .single)
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
sBuffer: .skip 500 // 500 bytes values zero
iInteger2: .skip 4 // 4 bytes value zero
dDoubleint2: .skip 8 // 8 bytes value zero
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: // entry of program
ldr x0,qAdriInteger2 // load variable address
mov x1,#100
str x1,[x0] // init variable iInteger2
100: // standard end of the program
mov x0, 0 // return code
mov x8, EXIT // request to exit program
svc 0 // perform the system call
qAdriInteger2: .quad iInteger2 // variable address iInteger2
|
http://rosettacode.org/wiki/Van_Eck_sequence | Van Eck sequence | The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occured previously.
Example
Using A:
0
Using B:
0 0
Using C:
0 0 1
Using B:
0 0 1 0
Using C: (zero last occurred two steps back - before the one)
0 0 1 0 2
Using B:
0 0 1 0 2 0
Using C: (two last occurred two steps back - before the zero)
0 0 1 0 2 0 2 2
Using C: (two last occurred one step back)
0 0 1 0 2 0 2 2 1
Using C: (one last appeared six steps back)
0 0 1 0 2 0 2 2 1 6
...
Task
Create a function/procedure/method/subroutine/... to generate the Van Eck sequence of numbers.
Use it to display here, on this page:
The first ten terms of the sequence.
Terms 991 - to - 1000 of the sequence.
References
Don't Know (the Van Eck Sequence) - Numberphile video.
Wikipedia Article: Van Eck's Sequence.
OEIS sequence: A181391.
| #ALGOL_68 | ALGOL 68 | BEGIN # find elements of the Van Eck Sequence - first term is 0, following #
# terms are 0 if the previous was the first appearance of the element #
# or how far back in the sequence the last element appeared #
# returns the first n elements of the Van Eck sequence #
OP VANECK = ( INT n )[]INT:
BEGIN
[ 1 : IF n < 0 THEN 0 ELSE n FI ]INT result; FOR i TO n DO result[ i ] := 0 OD;
[ 0 : UPB result ]INT pos; FOR i FROM 0 TO n DO pos[ i ] := 0 OD;
FOR i FROM 2 TO n DO
INT j = i - 1;
INT prev = result[ j ];
IF pos[ prev ] /= 0 THEN
# not a new element #
result[ i ] := j - pos[ prev ]
FI;
pos[ prev ] := j
OD;
result
END # VANECK # ;
# construct the first 1000 terms of the sequence #
[]INT seq = VANECK 1000;
# show the first and last 10 elements #
FOR i TO 10 DO print( ( " ", whole( seq[ i ], 0 ) ) ) OD;
print( ( newline ) );
FOR i FROM UPB seq - 9 TO UPB seq DO print( ( " ", whole( seq[ i ], 0 ) ) ) OD;
print( ( newline ) )
END |
http://rosettacode.org/wiki/Vampire_number | Vampire number | A vampire number is a natural decimal number with an even number of digits, that can be factored into two integers.
These two factors are called the fangs, and must have the following properties:
they each contain half the number of the decimal digits of the original number
together they consist of exactly the same decimal digits as the original number
at most one of them has a trailing zero
An example of a vampire number and its fangs: 1260 : (21, 60)
Task
Print the first 25 vampire numbers and their fangs.
Check if the following numbers are vampire numbers and, if so, print them and their fangs:
16758243290880, 24959017348650, 14593825548650
Note that a vampire number can have more than one pair of fangs.
See also
numberphile.com.
vampire search algorithm
vampire numbers on OEIS
| #C.23 | C# | using System;
namespace RosettaVampireNumber
{
class Program
{
static void Main(string[] args)
{
int i, j, n;
ulong x;
var f = new ulong[16];
var bigs = new ulong[] { 16758243290880UL, 24959017348650UL, 14593825548650UL, 0 };
ulong[] tens = new ulong[20];
tens[0] = 1;
for (i = 1; i < 20; i++)
tens[i] = tens[i - 1] * 10;
for (x = 1, n = 0; n < 25; x++)
{
if ((j = fangs(x, f, tens)) == 0) continue;
Console.Write(++n + ": ");
show_fangs(x, f, j);
}
Console.WriteLine();
for (i = 0; bigs[i] > 0 ; i++)
{
if ((j = fangs(bigs[i], f, tens)) > 0)
show_fangs(bigs[i], f, j);
else
Console.WriteLine(bigs[i] + " is not vampiric.");
}
Console.ReadLine();
}
private static void show_fangs(ulong x, ulong[] f, int cnt)
{
Console.Write(x);
int i;
for (i = 0; i < cnt; i++)
Console.Write(" = " + f[i] + " * " + (x / f[i]));
Console.WriteLine();
}
private static int fangs(ulong x, ulong[] f, ulong[] tens)
{
int n = 0;
int nd = ndigits(x);
if ((nd & 1) > 0) return 0;
nd /= 2;
ulong lo, hi;
lo = Math.Max(tens[nd - 1], (x + tens[nd] - 2) / (tens[nd] - 1));
hi = Math.Min(x / lo, (ulong) Math.Sqrt(x));
ulong a, b, t = dtally(x);
for (a = lo; a <= hi; a++)
{
b = x / a;
if (a * b == x && ((a % 10) > 0 || (b % 10) > 0) && t == dtally(a) + dtally(b))
f[n++] = a;
}
return n;
}
private static ulong dtally(ulong x)
{
ulong t = 0;
while (x > 0)
{
t += 1UL << (int)((x % 10) * 6);
x /= 10;
}
return t;
}
private static int ndigits(ulong x)
{
int n = 0;
while (x > 0)
{
n++;
x /= 10;
}
return n;
}
}
} |
http://rosettacode.org/wiki/Variable-length_quantity | Variable-length quantity | Implement some operations on variable-length quantities, at least including conversions from a normal number in the language to the binary representation of the variable-length quantity for that number, and vice versa. Any variants are acceptable.
Task
With above operations,
convert these two numbers 0x200000 (2097152 in decimal) and 0x1fffff (2097151 in decimal) into sequences of octets (an eight-bit byte);
display these sequences of octets;
convert these sequences of octets back to numbers, and check that they are equal to original numbers.
| #Phix | Phix | function vlq_encode(sequence s)
sequence res = {}
for i=length(s) to 1 by -1 do
integer n = s[i], msb = 0
if n<0 then crash("unsigned integers only!") end if
while 1 do
res = prepend(res,msb+and_bits(n,#7F))
n = floor(n/#80)
if n=0 then exit end if
msb = #80
end while
end for
return res
end function
function vlq_decode(sequence s)
sequence res = {}
for i=1 to length(s) do
integer si = s[i],
n = n*#80+and_bits(byte,#7F)
if not and_bits(si,#80) then
res = append(res,n)
n = 0
end if
end for
return res
end function
function svlg(sequence s)
string res = ""
for i=1 to length(s) do
res &= sprintf("#%02x:",{s[i]})
end for
return res[1..$-1]
end function
constant testNumbers = { #200000, #1FFFFF, 1, 127, 128 }
sequence s = vlq_encode(testNumbers),
decoded = vlq_decode(s)
printf(1,"%s -> %s -> %s\n",{svlg(testNumbers),svlg(s),svlg(decoded)})
if decoded!=testNumbers then crash("something wrong") end if
|
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function
| #Dyalect | Dyalect | func printAll(args...) {
for i in args {
print(i)
}
}
printAll("test", "rosetta code", 123, 5.6) |
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function
| #D.C3.A9j.C3.A0_Vu | Déjà Vu | show-all(:
while /= ) dup:
!.
drop
show-all( :foo "Hello" 42 [ true ] ) |
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Free_Pascal | Free Pascal | ' FB 1.05.0 Win64
Dim i As Integer
Dim l As Long
Dim s As Short
Dim b As Byte
Print "An integer occupies "; SizeOf(i); " bytes"
Print "A long occupies "; SizeOf(l); " bytes"
Print "A short occupies "; SizeOf(s); " bytes"
Print "A byte occupies "; SizeOf(b); " byte"
' or use type directly rather than a variable
Print "A boolean occupies "; SizeOf(Boolean); " byte"
Print "A single occupies "; SizeOf(Single); " bytes"
Print "A double occupies "; SizeOf(Double); " bytes"
Print
Print "Press any key to quit"
Sleep
|
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #FreeBASIC | FreeBASIC | ' FB 1.05.0 Win64
Dim i As Integer
Dim l As Long
Dim s As Short
Dim b As Byte
Print "An integer occupies "; SizeOf(i); " bytes"
Print "A long occupies "; SizeOf(l); " bytes"
Print "A short occupies "; SizeOf(s); " bytes"
Print "A byte occupies "; SizeOf(b); " byte"
' or use type directly rather than a variable
Print "A boolean occupies "; SizeOf(Boolean); " byte"
Print "A single occupies "; SizeOf(Single); " bytes"
Print "A double occupies "; SizeOf(Double); " bytes"
Print
Print "Press any key to quit"
Sleep
|
http://rosettacode.org/wiki/Vector | Vector | Task
Implement a Vector class (or a set of functions) that models a Physical Vector. The four basic operations and a pretty print function should be implemented.
The Vector may be initialized in any reasonable way.
Start and end points, and direction
Angular coefficient and value (length)
The four operations to be implemented are:
Vector + Vector addition
Vector - Vector subtraction
Vector * scalar multiplication
Vector / scalar division
| #Kotlin | Kotlin | // version 1.1.2
class Vector2D(val x: Double, val y: Double) {
operator fun plus(v: Vector2D) = Vector2D(x + v.x, y + v.y)
operator fun minus(v: Vector2D) = Vector2D(x - v.x, y - v.y)
operator fun times(s: Double) = Vector2D(s * x, s * y)
operator fun div(s: Double) = Vector2D(x / s, y / s)
override fun toString() = "($x, $y)"
}
operator fun Double.times(v: Vector2D) = v * this
fun main(args: Array<String>) {
val v1 = Vector2D(5.0, 7.0)
val v2 = Vector2D(2.0, 3.0)
println("v1 = $v1")
println("v2 = $v2")
println()
println("v1 + v2 = ${v1 + v2}")
println("v1 - v2 = ${v1 - v2}")
println("v1 * 11 = ${v1 * 11.0}")
println("11 * v2 = ${11.0 * v2}")
println("v1 / 2 = ${v1 / 2.0}")
} |
http://rosettacode.org/wiki/Verify_distribution_uniformity/Chi-squared_test | Verify distribution uniformity/Chi-squared test | Task
Write a function to verify that a given distribution of values is uniform by using the
χ
2
{\displaystyle \chi ^{2}}
test to see if the distribution has a likelihood of happening of at least the significance level (conventionally 5%).
The function should return a boolean that is true if the distribution is one that a uniform distribution (with appropriate number of degrees of freedom) may be expected to produce.
Reference
an entry at the MathWorld website: chi-squared distribution.
| #VBA | VBA | Private Function Test4DiscreteUniformDistribution(ObservationFrequencies() As Variant, Significance As Single) As Boolean
'Returns true if the observed frequencies pass the Pearson Chi-squared test at the required significance level.
Dim Total As Long, Ei As Long, i As Integer
Dim ChiSquared As Double, DegreesOfFreedom As Integer, p_value As Double
Debug.Print "[1] ""Data set:"" ";
For i = LBound(ObservationFrequencies) To UBound(ObservationFrequencies)
Total = Total + ObservationFrequencies(i)
Debug.Print ObservationFrequencies(i); " ";
Next i
DegreesOfFreedom = UBound(ObservationFrequencies) - LBound(ObservationFrequencies)
'This is exactly the number of different categories minus 1
Ei = Total / (DegreesOfFreedom + 1)
For i = LBound(ObservationFrequencies) To UBound(ObservationFrequencies)
ChiSquared = ChiSquared + (ObservationFrequencies(i) - Ei) ^ 2 / Ei
Next i
p_value = 1 - WorksheetFunction.ChiSq_Dist(ChiSquared, DegreesOfFreedom, True)
Debug.Print
Debug.Print " Chi-squared test for given frequencies"
Debug.Print "X-squared ="; ChiSquared; ", ";
Debug.Print "df ="; DegreesOfFreedom; ", ";
Debug.Print "p-value = "; Format(p_value, "0.0000")
Test4DiscreteUniformDistribution = p_value > Significance
End Function
Public Sub test()
Dim O() As Variant
O = [{199809,200665,199607,200270,199649}]
Debug.Print "[1] ""Uniform? "; Test4DiscreteUniformDistribution(O, 0.05); """"
O = [{522573,244456,139979,71531,21461}]
Debug.Print "[1] ""Uniform? "; Test4DiscreteUniformDistribution(O, 0.05); """"
End Sub |
http://rosettacode.org/wiki/Verify_distribution_uniformity/Chi-squared_test | Verify distribution uniformity/Chi-squared test | Task
Write a function to verify that a given distribution of values is uniform by using the
χ
2
{\displaystyle \chi ^{2}}
test to see if the distribution has a likelihood of happening of at least the significance level (conventionally 5%).
The function should return a boolean that is true if the distribution is one that a uniform distribution (with appropriate number of degrees of freedom) may be expected to produce.
Reference
an entry at the MathWorld website: chi-squared distribution.
| #Vlang | Vlang | import math
type Ifctn = fn(f64) f64
fn simpson38(f Ifctn, a f64, b f64, n int) f64 {
h := (b - a) / f64(n)
h1 := h / 3
mut sum := f(a) + f(b)
for j := 3*n - 1; j > 0; j-- {
if j%3 == 0 {
sum += 2 * f(a+h1*f64(j))
} else {
sum += 3 * f(a+h1*f64(j))
}
}
return h * sum / 8
}
fn gamma_inc_q(a f64, x f64) f64 {
aa1 := a - 1
f := Ifctn(fn[aa1](t f64) f64 {
return math.pow(t, aa1) * math.exp(-t)
})
mut y := aa1
h := 1.5e-2
for f(y)*(x-y) > 2e-8 && y < x {
y += .4
}
if y > x {
y = x
}
return 1 - simpson38(f, 0, y, int(y/h/math.gamma(a)))
}
fn chi2ud(ds []int) f64 {
mut sum, mut expected := 0.0,0.0
for d in ds {
expected += f64(d)
}
expected /= f64(ds.len)
for d in ds {
x := f64(d) - expected
sum += x * x
}
return sum / expected
}
fn chi2p(dof int, distance f64) f64 {
return gamma_inc_q(.5*f64(dof), .5*distance)
}
const sig_level = .05
fn main() {
for dset in [
[199809, 200665, 199607, 200270, 199649],
[522573, 244456, 139979, 71531, 21461],
] {
utest(dset)
}
}
fn utest(dset []int) {
println("Uniform distribution test")
mut sum := 0
for c in dset {
sum += c
}
println(" dataset: $dset")
println(" samples: $sum")
println(" categories: $dset.len")
dof := dset.len - 1
println(" degrees of freedom: $dof")
dist := chi2ud(dset)
println(" chi square test statistic: $dist")
p := chi2p(dof, dist)
println(" p-value of test statistic: $p")
sig := p < sig_level
println(" significant at ${sig_level*100:2.0f}% level? $sig")
println(" uniform? ${!sig}\n")
} |
http://rosettacode.org/wiki/Vigen%C3%A8re_cipher | Vigenère cipher | Task
Implement a Vigenère cypher, both encryption and decryption.
The program should handle keys and text of unequal length,
and should capitalize everything and discard non-alphabetic characters.
(If your program handles non-alphabetic characters in another way,
make a note of it.)
Related tasks
Caesar cipher
Rot-13
Substitution Cipher
| #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | encode[text_String, key_String] :=
Module[{textCode, keyCode},
textCode =
Cases[ToCharacterCode[
ToUpperCase@
text], _?(IntervalMemberQ[Interval@{65, 90}, #] &)] - 65;
keyCode =
Cases[ToCharacterCode[
ToUpperCase@
key], _?(IntervalMemberQ[Interval@{65, 90}, #] &)] - 65;
keyCode =
If[Length[textCode] < Length[keyCode],
keyCode[[;; Length@textCode]],
PadRight[keyCode, Length@textCode, keyCode]];
FromCharacterCode[Mod[textCode + keyCode, 26] + 65]]
decode[text_String, key_String] :=
Module[{textCode, keyCode},
textCode =
Cases[ToCharacterCode[
ToUpperCase@
text], _?(IntervalMemberQ[Interval@{65, 90}, #] &)] - 65;
keyCode =
Cases[ToCharacterCode[
ToUpperCase@
key], _?(IntervalMemberQ[Interval@{65, 90}, #] &)] - 65;
keyCode =
If[Length[textCode] < Length[keyCode],
keyCode[[;; Length@textCode]],
PadRight[keyCode, Length@textCode, keyCode]];
FromCharacterCode[Mod[textCode - keyCode, 26] + 65]] |
http://rosettacode.org/wiki/Visualize_a_tree | Visualize a tree | A tree structure (i.e. a rooted, connected acyclic graph) is often used in programming.
It's often helpful to visually examine such a structure.
There are many ways to represent trees to a reader, such as:
indented text (à la unix tree command)
nested HTML tables
hierarchical GUI widgets
2D or 3D images
etc.
Task
Write a program to produce a visual representation of some tree.
The content of the tree doesn't matter, nor does the output format, the only requirement being that the output is human friendly.
Make do with the vague term "friendly" the best you can.
| #Sidef | Sidef | func visualize_tree(tree, label, children,
indent = '',
mids = ['├─', '│ '],
ends = ['└─', ' '],
) {
func visit(node, pre) {
gather {
take(pre[0] + label(node))
var chldn = children(node)
var end = chldn.end
chldn.each_kv { |i, child|
if (i == end) { take(visit(child, [pre[1]] ~X+ ends)) }
else { take(visit(child, [pre[1]] ~X+ mids)) }
}
}
}
visit(tree, [indent] * 2)
}
var tree = 'root':['a':['a1':['a11':[]]],'b':['b1':['b11':[]],'b2':[],'b3':[]]]
say visualize_tree(tree, { .first }, { .second }).flatten.join("\n") |
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively (read a single directory).
| #Python | Python |
from pathlib import Path
for path in Path('.').rglob('*.*'):
print(path)
|
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively (read a single directory).
| #R | R | dir("/bar/foo", "mp3",recursive=T) |
http://rosettacode.org/wiki/Water_collected_between_towers | Water collected between towers | Task
In a two-dimensional world, we begin with any bar-chart (or row of close-packed 'towers', each of unit width), and then it rains,
completely filling all convex enclosures in the chart with water.
9 ██ 9 ██
8 ██ 8 ██
7 ██ ██ 7 ██≈≈≈≈≈≈≈≈██
6 ██ ██ ██ 6 ██≈≈██≈≈≈≈██
5 ██ ██ ██ ████ 5 ██≈≈██≈≈██≈≈████
4 ██ ██ ████████ 4 ██≈≈██≈≈████████
3 ██████ ████████ 3 ██████≈≈████████
2 ████████████████ ██ 2 ████████████████≈≈██
1 ████████████████████ 1 ████████████████████
In the example above, a bar chart representing the values [5, 3, 7, 2, 6, 4, 5, 9, 1, 2] has filled, collecting 14 units of water.
Write a function, in your language, from a given array of heights, to the number of water units that can be held in this way, by a corresponding bar chart.
Calculate the number of water units that could be collected by bar charts representing each of the following seven series:
[[1, 5, 3, 7, 2],
[5, 3, 7, 2, 6, 4, 5, 9, 1, 2],
[2, 6, 3, 5, 2, 8, 1, 4, 2, 2, 5, 3, 5, 7, 4, 1],
[5, 5, 5, 5],
[5, 6, 7, 8],
[8, 7, 7, 6],
[6, 7, 10, 7, 6]]
See, also:
Four Solutions to a Trivial Problem – a Google Tech Talk by Guy Steele
Water collected between towers on Stack Overflow, from which the example above is taken)
An interesting Haskell solution, using the Tardis monad, by Phil Freeman in a Github gist.
| #Scala | Scala | import scala.collection.parallel.CollectionConverters.VectorIsParallelizable
// Program to find maximum amount of water
// that can be trapped within given set of bars.
object TrappedWater extends App {
private val barLines = List(
Vector(1, 5, 3, 7, 2),
Vector(5, 3, 7, 2, 6, 4, 5, 9, 1, 2),
Vector(2, 6, 3, 5, 2, 8, 1, 4, 2, 2, 5, 3, 5, 7, 4, 1),
Vector(5, 5, 5, 5),
Vector(5, 6, 7, 8),
Vector(8, 7, 7, 6),
Vector(6, 7, 10, 7, 6)).zipWithIndex
// Method for maximum amount of water
private def sqBoxWater(barHeights: Vector[Int]): Int = {
def maxOfLeft = barHeights.par.scanLeft(0)(math.max).tail
def maxOfRight = barHeights.par.scanRight(0)(math.max).init
def waterlevels = maxOfLeft.zip(maxOfRight)
.map { case (maxL, maxR) => math.min(maxL, maxR) }
waterlevels.zip(barHeights).map { case (level, towerHeight) => level - towerHeight }.sum
}
barLines.foreach(barSet =>
println(s"Block ${barSet._2 + 1} could hold max. ${sqBoxWater(barSet._1)} units."))
} |
http://rosettacode.org/wiki/Vector_products | Vector products | A vector is defined as having three dimensions as being represented by an ordered collection of three numbers: (X, Y, Z).
If you imagine a graph with the x and y axis being at right angles to each other and having a third, z axis coming out of the page, then a triplet of numbers, (X, Y, Z) would represent a point in the region, and a vector from the origin to the point.
Given the vectors:
A = (a1, a2, a3)
B = (b1, b2, b3)
C = (c1, c2, c3)
then the following common vector products are defined:
The dot product (a scalar quantity)
A • B = a1b1 + a2b2 + a3b3
The cross product (a vector quantity)
A x B = (a2b3 - a3b2, a3b1 - a1b3, a1b2 - a2b1)
The scalar triple product (a scalar quantity)
A • (B x C)
The vector triple product (a vector quantity)
A x (B x C)
Task
Given the three vectors:
a = ( 3, 4, 5)
b = ( 4, 3, 5)
c = (-5, -12, -13)
Create a named function/subroutine/method to compute the dot product of two vectors.
Create a function to compute the cross product of two vectors.
Optionally create a function to compute the scalar triple product of three vectors.
Optionally create a function to compute the vector triple product of three vectors.
Compute and display: a • b
Compute and display: a x b
Compute and display: a • (b x c), the scalar triple product.
Compute and display: a x (b x c), the vector triple product.
References
A starting page on Wolfram MathWorld is Vector Multiplication .
Wikipedia dot product.
Wikipedia cross product.
Wikipedia triple product.
Related tasks
Dot product
Quaternion type
| #BASIC256 | BASIC256 |
a={3,4,5}:b={4,3,5}:c={-5,-12,-13}
print "A.B = "+dot_product(ref(a),ref(b))
call cross_product(ref(a),ref(b),ref(y))
Print "AxB = ("+y[0]+","+y[1]+","+y[2]+")"
print "A.(BxC) = "+s_tri(ref(a),ref(b),ref(c))
call v_tri(ref(a),ref(b),ref(c),ref(x),ref(y))
Print "A x (BxC) = ("+y[0]+","+y[1]+","+y[2]+")"
function dot_product(ref(x1),ref(x2))
dot_product= 0
for t = 0 to 2
dot_product += x1[t]*x2[t]
next t
end function
subroutine cross_product(ref(x1),ref(x2),ref(y1))
y1={0,0,0}
y1[0]=x1[1]*x2[2]-x1[2]*x2[1]
y1[1]=x1[2]*x2[0]-x1[0]*x2[2]
y1[2]=x1[0]*x2[1]-x1[1]*x2[0]
end subroutine
function s_tri(ref(x1),ref(x2),ref(x3))
call cross_product(ref(x2),ref(x3),ref(y1))
s_tri=dot_product(ref(x1),ref(y1))
end function
subroutine v_tri(ref(x1),ref(x2),ref(x3),ref(y1),ref(y2))
call cross_product(ref(x2),ref(x3),ref(y1))
call cross_product(ref(x1),ref(y1),ref(y2))
end subroutine
|
http://rosettacode.org/wiki/Validate_International_Securities_Identification_Number | Validate International Securities Identification Number | An International Securities Identification Number (ISIN) is a unique international identifier for a financial security such as a stock or bond.
Task
Write a function or program that takes a string as input, and checks whether it is a valid ISIN.
It is only valid if it has the correct format, and the embedded checksum is correct.
Demonstrate that your code passes the test-cases listed below.
Details
The format of an ISIN is as follows:
┌───────────── a 2-character ISO country code (A-Z)
│ ┌─────────── a 9-character security code (A-Z, 0-9)
│ │ ┌── a checksum digit (0-9)
AU0000XVGZA3
For this task, you may assume that any 2-character alphabetic sequence is a valid country code.
The checksum can be validated as follows:
Replace letters with digits, by converting each character from base 36 to base 10, e.g. AU0000XVGZA3 →1030000033311635103.
Perform the Luhn test on this base-10 number.
There is a separate task for this test: Luhn test of credit card numbers.
You don't have to replicate the implementation of this test here ─── you can just call the existing function from that task. (Add a comment stating if you did this.)
Test cases
ISIN
Validity
Comment
US0378331005
valid
US0373831005
not valid
The transposition typo is caught by the checksum constraint.
U50378331005
not valid
The substitution typo is caught by the format constraint.
US03378331005
not valid
The duplication typo is caught by the format constraint.
AU0000XVGZA3
valid
AU0000VXGZA3
valid
Unfortunately, not all transposition typos are caught by the checksum constraint.
FR0000988040
valid
(The comments are just informational. Your function should simply return a Boolean result. See #Raku for a reference solution.)
Related task:
Luhn test of credit card numbers
Also see
Interactive online ISIN validator
Wikipedia article: International Securities Identification Number
| #ALGOL_W | ALGOL W | begin
% external procedure that returns true if ccNumber passes the Luhn test, false otherwise %
logical procedure LuhnTest ( string(32) value ccNumber
; integer value ccLength
) ; algol "LUHN" ;
% returns true if isin is a valid ISIN, false otherwise %
logical procedure isIsin ( string(32) value isin ) ;
if isin( 12 // 20 ) not = "" then false % code is too long %
else begin
% the first two characters must be upper-case letters %
% returns the digit corresponding to a character of an ISIN %
integer procedure isinDigit ( string(1) value iChar ) ;
if iChar >= "0" and iChar <= "9" then ( decode( iChar ) - decode( "0" ) )
else if iChar >= "A" and iChar <= "Z" then ( decode( iChar ) - decode( "A" ) ) + 10
else begin % invalid digit %
isValid := false;
-1
end isinDigit ;
integer d1, d2;
logical isValid;
isValid := true;
d1 := isinDigit( isin( 0 // 1 ) );
d2 := isinDigit( isin( 1 // 1 ) );
if d1 < 10 or d1 > 35 or d2 < 10 or d2 > 35 then false % invalid first two characters %
else begin
% ok so far - conveet from base 36 to base 10 %
string(24) base10Isin;
integer b10Pos;
base10Isin := "";
b10Pos := 0;
for cPos := 0 until 10 do begin
integer digit;
digit := isinDigit( isin( cPos // 1 ) );
if isValid then begin
% valid digit %
if digit > 9 then begin
base10Isin( b10Pos // 1 ) := code( ( digit div 10 ) + decode( "0" ) );
b10Pos := b10Pos + 1;
end if_digit_gt_9 ;
base10Isin( b10Pos // 1 ) := code( ( digit rem 10 ) + decode( "0" ) );
b10Pos := b10Pos + 1
end if_isValid
end for_cPos ;
% add the check digit as is %
base10Isin( b10Pos // 1 ) := isin( 11 // 1 );
isValid and LuhnTest( base10Isin, b10Pos + 1 )
end
end isIsin ;
% task test cases %
procedure testIsIsin ( string(32) value isin
; logical value expected
) ;
begin
logical isValid;
isValid := isIsin( isin );
write( s_w := 0
, isin
, if isValid then " is valid" else " is invalid"
, if isValid = expected then "" else " NOT as expected ??"
)
end testIsin ;
testIsIsin( "US0378331005", true );
testIsIsin( "US0373831005", false );
testIsIsin( "U50378331005", false );
testIsIsin( "US03378331005", false );
testIsIsin( "AU0000XVGZA3", true );
testIsIsin( "AU0000VXGZA3", true );
testIsIsin( "FR0000988040", true );
end. |
http://rosettacode.org/wiki/Validate_International_Securities_Identification_Number | Validate International Securities Identification Number | An International Securities Identification Number (ISIN) is a unique international identifier for a financial security such as a stock or bond.
Task
Write a function or program that takes a string as input, and checks whether it is a valid ISIN.
It is only valid if it has the correct format, and the embedded checksum is correct.
Demonstrate that your code passes the test-cases listed below.
Details
The format of an ISIN is as follows:
┌───────────── a 2-character ISO country code (A-Z)
│ ┌─────────── a 9-character security code (A-Z, 0-9)
│ │ ┌── a checksum digit (0-9)
AU0000XVGZA3
For this task, you may assume that any 2-character alphabetic sequence is a valid country code.
The checksum can be validated as follows:
Replace letters with digits, by converting each character from base 36 to base 10, e.g. AU0000XVGZA3 →1030000033311635103.
Perform the Luhn test on this base-10 number.
There is a separate task for this test: Luhn test of credit card numbers.
You don't have to replicate the implementation of this test here ─── you can just call the existing function from that task. (Add a comment stating if you did this.)
Test cases
ISIN
Validity
Comment
US0378331005
valid
US0373831005
not valid
The transposition typo is caught by the checksum constraint.
U50378331005
not valid
The substitution typo is caught by the format constraint.
US03378331005
not valid
The duplication typo is caught by the format constraint.
AU0000XVGZA3
valid
AU0000VXGZA3
valid
Unfortunately, not all transposition typos are caught by the checksum constraint.
FR0000988040
valid
(The comments are just informational. Your function should simply return a Boolean result. See #Raku for a reference solution.)
Related task:
Luhn test of credit card numbers
Also see
Interactive online ISIN validator
Wikipedia article: International Securities Identification Number
| #AppleScript | AppleScript | use AppleScript version "2.4" -- OS X 10.10 (Yosemite) or later
use framework "Foundation"
on ISINTest(ISIN)
-- Check that the input is both text and 12 characters long …
if not ((ISIN's class is text) and ((count ISIN) is 12)) then return false
-- … and that it has the required format.
set ISIN to current application's class "NSMutableString"'s stringWithString:(ISIN)
if ((ISIN's rangeOfString:("^[A-Z]{2}[0-9A-Z]{9}[0-9]$") options:(current application's NSRegularExpressionSearch) range:({0, ISIN's |length|()}))'s |length|() is 0) then return false
-- Replace all letters with text representations of equivalent decimal numbers in the range 10 to 35.
set letterCharacters to characters of "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
repeat with i from 1 to 26
tell ISIN to replaceOccurrencesOfString:(item i of letterCharacters) withString:((i + 9) as text) options:(0) range:({0, its |length|()})
end repeat
-- Apply the Luhn test handler from the "Luhn test of credit card numbers" task.
-- <https://www.rosettacode.org/wiki/Luhn_test_of_credit_card_numbers#Straightforward>
return luhnTest(ISIN as text)
end ISINTest
-- Test code:
set testResults to {}
repeat with ISIN in {"US0378331005", "US0373831005", "U50378331005", "US03378331005", "AU0000XVGZA3", "AU0000VXGZA3", "FR0000988040"}
set end of testResults to {testNumber:ISIN's contents, valid:ISINTest(ISIN)}
end repeat
return testResults |
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #PL.2FM | PL/M | 100H:
/* CP/M BDOS SYSTEM CALL */
BDOS: PROCEDURE( FN, ARG ); DECLARE FN BYTE, ARG ADDRESS; GOTO 5;END;
/* CONSOLE OUTPUT ROUTINES */
PR$CHAR: PROCEDURE( C ); DECLARE C BYTE; CALL BDOS( 2, C ); END;
PR$STRING: PROCEDURE( S ); DECLARE S ADDRESS; CALL BDOS( 9, S ); END;
PR$NL: PROCEDURE; CALL PR$STRING( .( 0DH, 0AH, '$' ) ); END;
PR$NUMBER: PROCEDURE( N );
DECLARE N ADDRESS;
DECLARE V ADDRESS, N$STR( 6 ) BYTE INITIAL( '.....$' ), W BYTE;
N$STR( W := LAST( N$STR ) - 1 ) = '0' + ( ( V := N ) MOD 10 );
DO WHILE( ( V := V / 10 ) > 0 );
N$STR( W := W - 1 ) = '0' + ( V MOD 10 );
END;
CALL PR$STRING( .N$STR( W ) );
END PR$NUMBER;
/* TASK */
DECLARE S( 6 ) BYTE INITIAL( 1, 2, 2, 3, 4, 4, 5 );
DECLARE I BYTE;
DO I = 0 TO LAST( S );
DO;
DECLARE ( CURR, PREV ) BYTE;
CURR = S( I );
IF I > 1 AND CURR = PREV THEN DO;
CALL PR$NUMBER( I );
CALL PR$NL;
END;
PREV = CURR;
END;
END;
EOF |
http://rosettacode.org/wiki/Van_der_Corput_sequence | Van der Corput sequence | When counting integers in binary, if you put a (binary) point to the righEasyLangt of the count then the column immediately to the left denotes a digit with a multiplier of
2
0
{\displaystyle 2^{0}}
; the digit in the next column to the left has a multiplier of
2
1
{\displaystyle 2^{1}}
; and so on.
So in the following table:
0.
1.
10.
11.
...
the binary number "10" is
1
×
2
1
+
0
×
2
0
{\displaystyle 1\times 2^{1}+0\times 2^{0}}
.
You can also have binary digits to the right of the “point”, just as in the decimal number system. In that case, the digit in the place immediately to the right of the point has a weight of
2
−
1
{\displaystyle 2^{-1}}
, or
1
/
2
{\displaystyle 1/2}
.
The weight for the second column to the right of the point is
2
−
2
{\displaystyle 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
. And so on.
If you take the integer binary count of the first table, and reflect the digits about the binary point, you end up with the van der Corput sequence of numbers in base 2.
.0
.1
.01
.11
...
The third member of the sequence, binary 0.01, is therefore
0
×
2
−
1
+
1
×
2
−
2
{\displaystyle 0\times 2^{-1}+1\times 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
.
Distribution of 2500 points each: Van der Corput (top) vs pseudorandom
0
≤
x
<
1
{\displaystyle 0\leq x<1}
Monte Carlo simulations
This sequence is also a superset of the numbers representable by the "fraction" field of an old IEEE floating point standard. In that standard, the "fraction" field represented the fractional part of a binary number beginning with "1." e.g. 1.101001101.
Hint
A hint at a way to generate members of the sequence is to modify a routine used to change the base of an integer:
>>> def base10change(n, base):
digits = []
while n:
n,remainder = divmod(n, base)
digits.insert(0, remainder)
return digits
>>> base10change(11, 2)
[1, 0, 1, 1]
the above showing that 11 in decimal is
1
×
2
3
+
0
×
2
2
+
1
×
2
1
+
1
×
2
0
{\displaystyle 1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+1\times 2^{0}}
.
Reflected this would become .1101 or
1
×
2
−
1
+
1
×
2
−
2
+
0
×
2
−
3
+
1
×
2
−
4
{\displaystyle 1\times 2^{-1}+1\times 2^{-2}+0\times 2^{-3}+1\times 2^{-4}}
Task description
Create a function/method/routine that given n, generates the n'th term of the van der Corput sequence in base 2.
Use the function to compute and display the first ten members of the sequence. (The first member of the sequence is for n=0).
As a stretch goal/extra credit, compute and show members of the sequence for bases other than 2.
See also
The Basic Low Discrepancy Sequences
Non-decimal radices/Convert
Van der Corput sequence
| #Ada | Ada | with Ada.Text_IO;
procedure Main is
package Float_IO is new Ada.Text_IO.Float_IO (Float);
function Van_Der_Corput (N : Natural; Base : Positive := 2) return Float is
Value : Natural := N;
Result : Float := 0.0;
Exponent : Positive := 1;
begin
while Value > 0 loop
Result := Result +
Float (Value mod Base) / Float (Base ** Exponent);
Value := Value / Base;
Exponent := Exponent + 1;
end loop;
return Result;
end Van_Der_Corput;
begin
for Base in 2 .. 5 loop
Ada.Text_IO.Put ("Base" & Integer'Image (Base) & ":");
for N in 1 .. 10 loop
Ada.Text_IO.Put (' ');
Float_IO.Put (Item => Van_Der_Corput (N, Base), Exp => 0);
end loop;
Ada.Text_IO.New_Line;
end loop;
end Main; |
http://rosettacode.org/wiki/Van_der_Corput_sequence | Van der Corput sequence | When counting integers in binary, if you put a (binary) point to the righEasyLangt of the count then the column immediately to the left denotes a digit with a multiplier of
2
0
{\displaystyle 2^{0}}
; the digit in the next column to the left has a multiplier of
2
1
{\displaystyle 2^{1}}
; and so on.
So in the following table:
0.
1.
10.
11.
...
the binary number "10" is
1
×
2
1
+
0
×
2
0
{\displaystyle 1\times 2^{1}+0\times 2^{0}}
.
You can also have binary digits to the right of the “point”, just as in the decimal number system. In that case, the digit in the place immediately to the right of the point has a weight of
2
−
1
{\displaystyle 2^{-1}}
, or
1
/
2
{\displaystyle 1/2}
.
The weight for the second column to the right of the point is
2
−
2
{\displaystyle 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
. And so on.
If you take the integer binary count of the first table, and reflect the digits about the binary point, you end up with the van der Corput sequence of numbers in base 2.
.0
.1
.01
.11
...
The third member of the sequence, binary 0.01, is therefore
0
×
2
−
1
+
1
×
2
−
2
{\displaystyle 0\times 2^{-1}+1\times 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
.
Distribution of 2500 points each: Van der Corput (top) vs pseudorandom
0
≤
x
<
1
{\displaystyle 0\leq x<1}
Monte Carlo simulations
This sequence is also a superset of the numbers representable by the "fraction" field of an old IEEE floating point standard. In that standard, the "fraction" field represented the fractional part of a binary number beginning with "1." e.g. 1.101001101.
Hint
A hint at a way to generate members of the sequence is to modify a routine used to change the base of an integer:
>>> def base10change(n, base):
digits = []
while n:
n,remainder = divmod(n, base)
digits.insert(0, remainder)
return digits
>>> base10change(11, 2)
[1, 0, 1, 1]
the above showing that 11 in decimal is
1
×
2
3
+
0
×
2
2
+
1
×
2
1
+
1
×
2
0
{\displaystyle 1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+1\times 2^{0}}
.
Reflected this would become .1101 or
1
×
2
−
1
+
1
×
2
−
2
+
0
×
2
−
3
+
1
×
2
−
4
{\displaystyle 1\times 2^{-1}+1\times 2^{-2}+0\times 2^{-3}+1\times 2^{-4}}
Task description
Create a function/method/routine that given n, generates the n'th term of the van der Corput sequence in base 2.
Use the function to compute and display the first ten members of the sequence. (The first member of the sequence is for n=0).
As a stretch goal/extra credit, compute and show members of the sequence for bases other than 2.
See also
The Basic Low Discrepancy Sequences
Non-decimal radices/Convert
Van der Corput sequence
| #AutoHotkey | AutoHotkey | SetFormat, FloatFast, 0.5
for i, v in [2, 3, 4, 5, 6] {
seq .= "Base " v ": "
Loop, 10
seq .= VanDerCorput(A_Index - 1, v) (A_Index = 10 ? "`n" : ", ")
}
MsgBox, % seq
VanDerCorput(n, b, r=0) {
while n
r += Mod(n, b) * b ** -A_Index, n := n // b
return, r
} |
http://rosettacode.org/wiki/Variables | Variables | Task
Demonstrate a language's methods of:
variable declaration
initialization
assignment
datatypes
scope
referencing, and
other variable related facilities
| #Ada | Ada | Name: declare -- a local declaration block has an optional name
A : constant Integer := 42; -- Create a constant
X : String := "Hello"; -- Create and initialize a local variable
Y : Integer; -- Create an uninitialized variable
Z : Integer renames Y: -- Rename Y (creates a view)
function F (X: Integer) return Integer is
-- Inside, all declarations outside are visible when not hidden: X, Y, Z are global with respect to F.
X: Integer := Z; -- hides the outer X which however can be referred to by Name.X
begin
...
end F; -- locally declared variables stop to exist here
begin
Y := 1; -- Assign variable
declare
X: Float := -42.0E-10; -- hides the outer X (can be referred to Name.X like in F)
begin
...
end;
end Name; -- End of the scope |
http://rosettacode.org/wiki/Van_Eck_sequence | Van Eck sequence | The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occured previously.
Example
Using A:
0
Using B:
0 0
Using C:
0 0 1
Using B:
0 0 1 0
Using C: (zero last occurred two steps back - before the one)
0 0 1 0 2
Using B:
0 0 1 0 2 0
Using C: (two last occurred two steps back - before the zero)
0 0 1 0 2 0 2 2
Using C: (two last occurred one step back)
0 0 1 0 2 0 2 2 1
Using C: (one last appeared six steps back)
0 0 1 0 2 0 2 2 1 6
...
Task
Create a function/procedure/method/subroutine/... to generate the Van Eck sequence of numbers.
Use it to display here, on this page:
The first ten terms of the sequence.
Terms 991 - to - 1000 of the sequence.
References
Don't Know (the Van Eck Sequence) - Numberphile video.
Wikipedia Article: Van Eck's Sequence.
OEIS sequence: A181391.
| #ALGOL-M | ALGOL-M | begin
integer array eck[1:1000];
integer i, j;
for i := 1 step 1 until 1000 do
eck[i] := 0;
for i := 1 step 1 until 999 do
begin
j := i - 1;
while j > 0 and eck[i] <> eck[j] do
j := j - 1;
if j <> 0 then
eck[i+1] := i - j;
end;
for i := 1 step 1 until 10 do
writeon(eck[i]);
write("");
for i := 991 step 1 until 1000 do
writeon(eck[i]);
end |
http://rosettacode.org/wiki/Van_Eck_sequence | Van Eck sequence | The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occured previously.
Example
Using A:
0
Using B:
0 0
Using C:
0 0 1
Using B:
0 0 1 0
Using C: (zero last occurred two steps back - before the one)
0 0 1 0 2
Using B:
0 0 1 0 2 0
Using C: (two last occurred two steps back - before the zero)
0 0 1 0 2 0 2 2
Using C: (two last occurred one step back)
0 0 1 0 2 0 2 2 1
Using C: (one last appeared six steps back)
0 0 1 0 2 0 2 2 1 6
...
Task
Create a function/procedure/method/subroutine/... to generate the Van Eck sequence of numbers.
Use it to display here, on this page:
The first ten terms of the sequence.
Terms 991 - to - 1000 of the sequence.
References
Don't Know (the Van Eck Sequence) - Numberphile video.
Wikipedia Article: Van Eck's Sequence.
OEIS sequence: A181391.
| #ALGOL_W | ALGOL W | begin % find elements of the Van Eck Sequence - first term is 0, following %
% terms are 0 if the previous was the first appearance of the element %
% or how far back in the sequence the last element appeared %
% sets s to the first n elements of the Van Eck sequence %
procedure VanEck ( integer array s ( * ) ; integer value n ) ;
begin
integer array pos ( 0 :: n );
for i := 1 until n do s( i ) := 0;
for i := 0 until n do pos( i ) := 0;
for i := 2 until n do begin
integer j, prev;
j := i - 1;
prev := s( j );
if pos( prev ) not = 0 then begin
% not a new element %
s( i ) := j - pos( prev )
end if_pos_prev_ne_0 ;
pos( prev ) := j
end for_j;
end VanEck ;
% construct the first 1000 terms of the sequence %
integer MAX_VAN_ECK;
MAX_VAN_ECK := 1000;
begin
integer array seq ( 1 :: MAX_VAN_ECK );
VanEck( seq, MAX_VAN_ECK );
% show the first and last 10 elements %
for i := 1 until 10 do writeon( i_w := 1, s_w := 0, " ", seq( i ) );
write();
for i := MAX_VAN_ECK - 9 until MAX_VAN_ECK do writeon( i_w := 1, s_w := 0, " ", seq( i ) );
write()
end
end. |
http://rosettacode.org/wiki/Vampire_number | Vampire number | A vampire number is a natural decimal number with an even number of digits, that can be factored into two integers.
These two factors are called the fangs, and must have the following properties:
they each contain half the number of the decimal digits of the original number
together they consist of exactly the same decimal digits as the original number
at most one of them has a trailing zero
An example of a vampire number and its fangs: 1260 : (21, 60)
Task
Print the first 25 vampire numbers and their fangs.
Check if the following numbers are vampire numbers and, if so, print them and their fangs:
16758243290880, 24959017348650, 14593825548650
Note that a vampire number can have more than one pair of fangs.
See also
numberphile.com.
vampire search algorithm
vampire numbers on OEIS
| #C.2B.2B | C++ | #include <vector>
#include <utility>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <string>
#include <cmath>
bool isVampireNumber( long number, std::vector<std::pair<long, long> > & solution ) {
std::ostringstream numberstream ;
numberstream << number ;
std::string numberstring( numberstream.str( ) ) ;
std::sort ( numberstring.begin( ) , numberstring.end( ) ) ;
int fanglength = numberstring.length( ) / 2 ;
long start = static_cast<long>( std::pow( 10 , fanglength - 1 ) ) ;
long end = sqrt(number) ;
for ( long i = start ; i <= end ; i++ ) {
if ( number % i == 0 ) {
long quotient = number / i ;
if ( ( i % 10 == 0 ) && ( quotient % 10 == 0 ) )
continue ;
numberstream.str( "" ) ; //clear the number stream
numberstream << i << quotient ;
std::string divisorstring ( numberstream.str( ) ) ;
std::sort ( divisorstring.begin( ) , divisorstring.end( ) ) ;
if ( divisorstring == numberstring ) {
std::pair<long , long> divisors = std::make_pair( i, quotient ) ;
solution.push_back( divisors ) ;
}
}
}
return !solution.empty( ) ;
}
void printOut( const std::pair<long, long> & solution ) {
std::cout << "[ " << solution.first << " , " << solution.second << " ]" ;
}
int main( ) {
int vampireNumbersFound = 0 ;
std::vector<std::pair<long , long> > solutions ;
double i = 1.0 ;
while ( vampireNumbersFound < 25 ) {
long start = static_cast<long>( std::pow( 10 , i ) ) ;
long end = start * 10 ;
for ( long num = start ; num < end ; num++ ) {
if ( isVampireNumber( num , solutions ) ) {
vampireNumbersFound++ ;
std::cout << vampireNumbersFound << " :" << num << " is a vampire number! These are the fangs:\n" ;
std::for_each( solutions.begin( ) , solutions.end( ) , printOut ) ;
std::cout << "\n_______________" << std::endl ;
solutions.clear( ) ;
if ( vampireNumbersFound == 25 )
break ;
}
}
i += 2.0 ;
}
std::vector<long> testnumbers ;
testnumbers.push_back( 16758243290880 ) ;
testnumbers.push_back( 24959017348650 ) ;
testnumbers.push_back( 14593825548650 ) ;
for ( std::vector<long>::const_iterator svl = testnumbers.begin( ) ;
svl != testnumbers.end( ) ; svl++ ) {
if ( isVampireNumber( *svl , solutions ) ) {
std::cout << *svl << " is a vampire number! The fangs:\n" ;
std::for_each( solutions.begin( ) , solutions.end( ) , printOut ) ;
std::cout << std::endl ;
solutions.clear( ) ;
} else {
std::cout << *svl << " is not a vampire number!" << std::endl ;
}
}
return 0 ;
} |
http://rosettacode.org/wiki/Variable-length_quantity | Variable-length quantity | Implement some operations on variable-length quantities, at least including conversions from a normal number in the language to the binary representation of the variable-length quantity for that number, and vice versa. Any variants are acceptable.
Task
With above operations,
convert these two numbers 0x200000 (2097152 in decimal) and 0x1fffff (2097151 in decimal) into sequences of octets (an eight-bit byte);
display these sequences of octets;
convert these sequences of octets back to numbers, and check that they are equal to original numbers.
| #PicoLisp | PicoLisp | (de numToVlq (Num)
(let Res (cons (& Num 127))
(while (gt0 (setq Num (>> 7 Num)))
(push 'Res (| 128 (& Num 127))) )
Res ) )
(de vlqToNum (Vlq)
(let Res 0
(for N Vlq
(setq Res (| (>> -7 Res) (& N 127))) ) ) )
(for Num (0 15 16 127 128 255 2097151 2097152)
(let Vlq (numToVlq Num)
(tab (12 12 12) Num (glue ":" (mapcar hex Vlq)) (vlqToNum Vlq)) ) ) |
http://rosettacode.org/wiki/Variable-length_quantity | Variable-length quantity | Implement some operations on variable-length quantities, at least including conversions from a normal number in the language to the binary representation of the variable-length quantity for that number, and vice versa. Any variants are acceptable.
Task
With above operations,
convert these two numbers 0x200000 (2097152 in decimal) and 0x1fffff (2097151 in decimal) into sequences of octets (an eight-bit byte);
display these sequences of octets;
convert these sequences of octets back to numbers, and check that they are equal to original numbers.
| #PL.2FI | PL/I |
test: procedure options(main);
declare s character (20) varying;
declare c character (1);
declare v fixed binary (31);
declare (i, k) fixed binary;
get edit (s) (L);
s = trim (s);
v = 0;
do i = 1 to length(s);
c = substr(s, i, 1);
k = index('0123456789abcdef', c);
if k > 0 then v = v*16 + k - 1;
end;
put skip data (s, v);
/* Convert back to hex */
declare hex character(16) initial ('0123456789abcdef');
declare hs character (20) initial ('');
declare d fixed binary;
do i = length(hs) to 1 by -1 until (v = 0);
d = mod(v, 16) + 1;
substr(hs, i, 1) = substr(hex, d, 1);
v = v/16;
end;
put skip list (hs);
end test;
|
http://rosettacode.org/wiki/Variable-length_quantity | Variable-length quantity | Implement some operations on variable-length quantities, at least including conversions from a normal number in the language to the binary representation of the variable-length quantity for that number, and vice versa. Any variants are acceptable.
Task
With above operations,
convert these two numbers 0x200000 (2097152 in decimal) and 0x1fffff (2097151 in decimal) into sequences of octets (an eight-bit byte);
display these sequences of octets;
convert these sequences of octets back to numbers, and check that they are equal to original numbers.
| #Python | Python | def tobits(n, _group=8, _sep='_', _pad=False):
'Express n as binary bits with separator'
bits = '{0:b}'.format(n)[::-1]
if _pad:
bits = '{0:0{1}b}'.format(n,
((_group+len(bits)-1)//_group)*_group)[::-1]
answer = _sep.join(bits[i:i+_group]
for i in range(0, len(bits), _group))[::-1]
answer = '0'*(len(_sep)-1) + answer
else:
answer = _sep.join(bits[i:i+_group]
for i in range(0, len(bits), _group))[::-1]
return answer
def tovlq(n):
return tobits(n, _group=7, _sep='1_', _pad=True)
def toint(vlq):
return int(''.join(vlq.split('_1')), 2)
def vlqsend(vlq):
for i, byte in enumerate(vlq.split('_')[::-1]):
print('Sent byte {0:3}: {1:#04x}'.format(i, int(byte,2))) |
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function
| #E | E | def example {
match [`run`, args] {
for x in args {
println(x)
}
}
}
example("Mary", "had", "a", "little", "lamb")
E.call(example, "run", ["Mary", "had", "a", "little", "lamb"]) |
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function
| #Egel | Egel |
[ X Y -> "two" | X -> "one" | -> "zero" ]
|
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Gambas | Gambas | Public Sub Main()
Print "Boolean =\t " & SizeOf(gb.Boolean)
Print "Byte =\t\t " & SizeOf(gb.Byte)
Print "Short =\t\t " & SizeOf(gb.Short)
Print "Integer =\t " & SizeOf(gb.Integer)
Print "Single =\t " & SizeOf(gb.Single)
Print "Long =\t\t " & SizeOf(gb.Long)
Print "Float =\t\t " & SizeOf(gb.Float)
Print "Date =\t\t " & SizeOf(gb.Date)
Print "String =\t " & SizeOf(gb.String)
Print "Object =\t " & SizeOf(gb.Object)
Print "Pointer =\t " & SizeOf(gb.Pointer)
Print "Variant =\t " & SizeOf(gb.Variant)
End |
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Go | Go | import "unsafe"
unsafe.Sizeof(x) |
http://rosettacode.org/wiki/Vector | Vector | Task
Implement a Vector class (or a set of functions) that models a Physical Vector. The four basic operations and a pretty print function should be implemented.
The Vector may be initialized in any reasonable way.
Start and end points, and direction
Angular coefficient and value (length)
The four operations to be implemented are:
Vector + Vector addition
Vector - Vector subtraction
Vector * scalar multiplication
Vector / scalar division
| #Lua | Lua | vector = {mt = {}}
function vector.new (x, y)
local new = {x = x or 0, y = y or 0}
setmetatable(new, vector.mt)
return new
end
function vector.mt.__add (v1, v2)
return vector.new(v1.x + v2.x, v1.y + v2.y)
end
function vector.mt.__sub (v1, v2)
return vector.new(v1.x - v2.x, v1.y - v2.y)
end
function vector.mt.__mul (v, s)
return vector.new(v.x * s, v.y * s)
end
function vector.mt.__div (v, s)
return vector.new(v.x / s, v.y / s)
end
function vector.print (vec)
print("(" .. vec.x .. ", " .. vec.y .. ")")
end
local a, b = vector.new(5, 7), vector.new(2, 3)
vector.print(a + b)
vector.print(a - b)
vector.print(a * 11)
vector.print(a / 2) |
http://rosettacode.org/wiki/Verify_distribution_uniformity/Chi-squared_test | Verify distribution uniformity/Chi-squared test | Task
Write a function to verify that a given distribution of values is uniform by using the
χ
2
{\displaystyle \chi ^{2}}
test to see if the distribution has a likelihood of happening of at least the significance level (conventionally 5%).
The function should return a boolean that is true if the distribution is one that a uniform distribution (with appropriate number of degrees of freedom) may be expected to produce.
Reference
an entry at the MathWorld website: chi-squared distribution.
| #Wren | Wren | import "/math" for Math, Nums
import "/fmt" for Fmt
var integrate = Fn.new { |a, b, n, f|
var h = (b - a) / n
var sum = 0
for (i in 0...n) {
var x = a + i*h
sum = sum + (f.call(x) + 4 * f.call(x + h/2) + f.call(x + h)) / 6
}
return sum * h
}
var gammaIncomplete = Fn.new { |a, x|
var am1 = a - 1
var f0 = Fn.new { |t| t.pow(am1) * (-t).exp }
var h = 1.5e-2
var y = am1
while ((f0.call(y) * (x - y) > 2e-8) && y < x) y = y + 0.4
if (y > x) y = x
return 1 - integrate.call(0, y, (y/h).truncate, f0) / Math.gamma(a)
}
var chi2UniformDistance = Fn.new { |ds|
var expected = Nums.mean(ds)
var sum = Nums.sum(ds.map { |d| (d - expected).pow(2) }.toList)
return sum / expected
}
var chi2Probability = Fn.new { |dof, dist| gammaIncomplete.call(0.5*dof, 0.5*dist) }
var chiIsUniform = Fn.new { |ds, significance|
var dof = ds.count - 1
var dist = chi2UniformDistance.call(ds)
return chi2Probability.call(dof, dist) > significance
}
var dsets = [
[199809, 200665, 199607, 200270, 199649],
[522573, 244456, 139979, 71531, 21461]
]
for (ds in dsets) {
System.print("Dataset: %(ds)")
var dist = chi2UniformDistance.call(ds)
var dof = ds.count - 1
Fmt.write("DOF: $d Distance: $.4f", dof, dist)
var prob = chi2Probability.call(dof, dist)
Fmt.write(" Probability: $.6f", prob)
var uniform = chiIsUniform.call(ds, 0.05) ? "Yes" : "No"
System.print(" Uniform? %(uniform)\n")
} |
http://rosettacode.org/wiki/Vigen%C3%A8re_cipher | Vigenère cipher | Task
Implement a Vigenère cypher, both encryption and decryption.
The program should handle keys and text of unequal length,
and should capitalize everything and discard non-alphabetic characters.
(If your program handles non-alphabetic characters in another way,
make a note of it.)
Related tasks
Caesar cipher
Rot-13
Substitution Cipher
| #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref savelog symbols nobinary
pt = 'Attack at dawn!'
key = 'LEMON'
test(key, pt)
key = 'N' -- rot-13
test(key, pt)
key = 'B' -- Caesar
test(key, pt)
pt = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
key = 'A'
test(key, pt)
pt = sampledata()
key = 'Hamlet; Prince of Denmark'
test(key, pt)
return
method vigenere(meth, key, text) public static
select
when 'encipher'.abbrev(meth.lower, 1) then df = 1
when 'decipher'.abbrev(meth.lower, 1) then df = -1
otherwise signal IllegalArgumentException(meth 'must be "encipher" or "decipher"')
end
alpha = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
text = stringscrubber(text)
key = stringscrubber(key)
code = ''
loop l_ = 1 to text.length()
M = alpha.pos(text.substr(l_, 1)) - 1
k_ = (l_ - 1) // key.length()
K = alpha.pos(key.substr(k_ + 1, 1)) - 1
C = mod((M + K * df), alpha.length())
C = alpha.substr(C + 1, 1)
code = code || C
end l_
return code
method vigenere_encipher(key, plaintext) public static
return vigenere('encipher', key, plaintext)
method vigenere_decipher(key, ciphertext) public static
return vigenere('decipher', key, ciphertext)
method mod(N = int, D = int) private static
return (D + (N // D)) // D
method stringscrubber(cleanup) private static
alpha = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
cleanup = cleanup.upper.space(0)
loop label f_ forever
x_ = cleanup.verify(alpha)
if x_ = 0 then leave f_
cleanup = cleanup.changestr(cleanup.substr(x_, 1), '')
end f_
return cleanup
method test(key, pt) private static
ct = vigenere_encipher(key, pt)
display(ct)
dt = vigenere_decipher(key, ct)
display(dt)
return
method display(text) public static
line = ''
o_ = 0
loop c_ = 1 to text.length()
b_ = o_ // 5
o_ = o_ + 1
if b_ = 0 then line = line' '
line = line || text.substr(c_, 1)
end c_
say '....+....|'.copies(8)
loop label l_ forever
parse line w1 w2 w3 w4 w5 w6 W7 w8 w9 w10 w11 w12 line
pline = w1 w2 w3 w4 w5 w6 w7 w8 w9 w10 w11 w12
say pline.strip()
if line.strip().length() = 0 then leave l_
end l_
say
return
method sampledata() private static returns Rexx
NL = char('\n')
antic_disposition = Rexx[]
antic_disposition = [ -
Rexx("To be, or not to be--that is the question:" ), -
Rexx("Whether 'tis nobler in the mind to suffer" ), -
Rexx("The slings and arrows of outrageous fortune" ), -
Rexx("Or to take arms against a sea of troubles" ), -
Rexx("And by opposing end them. To die, to sleep--" ), -
Rexx("No more--and by a sleep to say we end" ), -
Rexx("The heartache, and the thousand natural shocks" ), -
Rexx("That flesh is heir to. 'Tis a consummation" ), -
Rexx("Devoutly to be wished. To die, to sleep--" ), -
Rexx("To sleep--perchance to dream: ay, there's the rub,"), -
Rexx("For in that sleep of death what dreams may come" ), -
Rexx("When we have shuffled off this mortal coil," ), -
Rexx("Must give us pause. There's the respect" ), -
Rexx("That makes calamity of so long life." ), -
Rexx("For who would bear the whips and scorns of time," ), -
Rexx("Th' oppressor's wrong, the proud man's contumely" ), -
Rexx("The pangs of despised love, the law's delay," ), -
Rexx("The insolence of office, and the spurns" ), -
Rexx("That patient merit of th' unworthy takes," ), -
Rexx("When he himself might his quietus make" ), -
Rexx("With a bare bodkin? Who would fardels bear," ), -
Rexx("To grunt and sweat under a weary life," ), -
Rexx("But that the dread of something after death," ), -
Rexx("The undiscovered country, from whose bourn" ), -
Rexx("No traveller returns, puzzles the will," ), -
Rexx("And makes us rather bear those ills we have" ), -
Rexx("Than fly to others that we know not of?" ), -
Rexx("Thus conscience does make cowards of us all," ), -
Rexx("And thus the native hue of resolution" ), -
Rexx("Is sicklied o'er with the pale cast of thought," ), -
Rexx("And enterprise of great pith and moment" ), -
Rexx("With this regard their currents turn awry" ), -
Rexx("And lose the name of action. -- Soft you now," ), -
Rexx("The fair Ophelia! -- Nymph, in thy orisons" ), -
Rexx("Be all my sins remembered." ) -
]
melancholy_dane = Rexx('')
loop l_ = 0 for antic_disposition.length
melancholy_dane = melancholy_dane || antic_disposition[l_] || NL
end l_
return melancholy_dane
|
http://rosettacode.org/wiki/Visualize_a_tree | Visualize a tree | A tree structure (i.e. a rooted, connected acyclic graph) is often used in programming.
It's often helpful to visually examine such a structure.
There are many ways to represent trees to a reader, such as:
indented text (à la unix tree command)
nested HTML tables
hierarchical GUI widgets
2D or 3D images
etc.
Task
Write a program to produce a visual representation of some tree.
The content of the tree doesn't matter, nor does the output format, the only requirement being that the output is human friendly.
Make do with the vague term "friendly" the best you can.
| #Tcl | Tcl | package require struct::tree
proc visualize_tree {tree {nameattr name}} {
set path {}
$tree walk [$tree rootname] -order both {mode node} {
if {$mode eq "enter"} {
set s ""
foreach p $path {
append s [expr {[$tree next $p] eq "" ? " " : "\u2502 "}]
}
lappend path $node
append s [expr {
[$tree next $node] eq "" ? "\u2514\u2500" : "\u251c\u2500"
}]
if {[$tree keyexists $node $nameattr]} {
set name [$tree get $node $nameattr]
} else {
# No node name attribute; use the raw name
set name $node
}
puts "$s$name"
} else {
set path [lrange $path 0 end-1]
}
}
} |
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively (read a single directory).
| #Racket | Racket |
-> (for ([f (in-directory "/tmp")] #:when (regexp-match? "\\.rkt$" f))
(displayln f))
... *.rkt files including in nested directories ...
|
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively (read a single directory).
| #Raku | Raku | use File::Find;
.say for find dir => '.', name => /'.txt' $/; |
http://rosettacode.org/wiki/Water_collected_between_towers | Water collected between towers | Task
In a two-dimensional world, we begin with any bar-chart (or row of close-packed 'towers', each of unit width), and then it rains,
completely filling all convex enclosures in the chart with water.
9 ██ 9 ██
8 ██ 8 ██
7 ██ ██ 7 ██≈≈≈≈≈≈≈≈██
6 ██ ██ ██ 6 ██≈≈██≈≈≈≈██
5 ██ ██ ██ ████ 5 ██≈≈██≈≈██≈≈████
4 ██ ██ ████████ 4 ██≈≈██≈≈████████
3 ██████ ████████ 3 ██████≈≈████████
2 ████████████████ ██ 2 ████████████████≈≈██
1 ████████████████████ 1 ████████████████████
In the example above, a bar chart representing the values [5, 3, 7, 2, 6, 4, 5, 9, 1, 2] has filled, collecting 14 units of water.
Write a function, in your language, from a given array of heights, to the number of water units that can be held in this way, by a corresponding bar chart.
Calculate the number of water units that could be collected by bar charts representing each of the following seven series:
[[1, 5, 3, 7, 2],
[5, 3, 7, 2, 6, 4, 5, 9, 1, 2],
[2, 6, 3, 5, 2, 8, 1, 4, 2, 2, 5, 3, 5, 7, 4, 1],
[5, 5, 5, 5],
[5, 6, 7, 8],
[8, 7, 7, 6],
[6, 7, 10, 7, 6]]
See, also:
Four Solutions to a Trivial Problem – a Google Tech Talk by Guy Steele
Water collected between towers on Stack Overflow, from which the example above is taken)
An interesting Haskell solution, using the Tardis monad, by Phil Freeman in a Github gist.
| #Scheme | Scheme | (import (scheme base)
(scheme write))
(define (total-collected chart)
(define (highest-left vals curr)
(if (null? vals)
(list curr)
(cons curr
(highest-left (cdr vals) (max (car vals) curr)))))
(define (highest-right vals curr)
(reverse (highest-left (reverse vals) curr)))
;
(if (< (length chart) 3) ; catch the end cases
0
(apply +
(map (lambda (l c r)
(if (or (<= l c)
(<= r c))
0
(- (min l r) c)))
(highest-left chart 0)
chart
(highest-right chart 0)))))
(for-each
(lambda (chart)
(display chart) (display " -> ") (display (total-collected chart)) (newline))
'((1 5 3 7 2)
(5 3 7 2 6 4 5 9 1 2)
(2 6 3 5 2 8 1 4 2 2 5 3 5 7 4 1)
(5 5 5 5)
(5 6 7 8)
(8 7 7 6)
(6 7 10 7 6))) |
http://rosettacode.org/wiki/Vector_products | Vector products | A vector is defined as having three dimensions as being represented by an ordered collection of three numbers: (X, Y, Z).
If you imagine a graph with the x and y axis being at right angles to each other and having a third, z axis coming out of the page, then a triplet of numbers, (X, Y, Z) would represent a point in the region, and a vector from the origin to the point.
Given the vectors:
A = (a1, a2, a3)
B = (b1, b2, b3)
C = (c1, c2, c3)
then the following common vector products are defined:
The dot product (a scalar quantity)
A • B = a1b1 + a2b2 + a3b3
The cross product (a vector quantity)
A x B = (a2b3 - a3b2, a3b1 - a1b3, a1b2 - a2b1)
The scalar triple product (a scalar quantity)
A • (B x C)
The vector triple product (a vector quantity)
A x (B x C)
Task
Given the three vectors:
a = ( 3, 4, 5)
b = ( 4, 3, 5)
c = (-5, -12, -13)
Create a named function/subroutine/method to compute the dot product of two vectors.
Create a function to compute the cross product of two vectors.
Optionally create a function to compute the scalar triple product of three vectors.
Optionally create a function to compute the vector triple product of three vectors.
Compute and display: a • b
Compute and display: a x b
Compute and display: a • (b x c), the scalar triple product.
Compute and display: a x (b x c), the vector triple product.
References
A starting page on Wolfram MathWorld is Vector Multiplication .
Wikipedia dot product.
Wikipedia cross product.
Wikipedia triple product.
Related tasks
Dot product
Quaternion type
| #BBC_BASIC | BBC BASIC | DIM a(2), b(2), c(2), d(2)
a() = 3, 4, 5
b() = 4, 3, 5
c() = -5, -12, -13
PRINT "a . b = "; FNdot(a(),b())
PROCcross(a(),b(),d())
PRINT "a x b = (";d(0)", ";d(1)", ";d(2)")"
PRINT "a . (b x c) = "; FNscalartriple(a(),b(),c())
PROCvectortriple(a(),b(),c(),d())
PRINT "a x (b x c) = (";d(0)", ";d(1)", ";d(2)")"
END
DEF FNdot(A(),B())
LOCAL C() : DIM C(0,0)
C() = A().B()
= C(0,0)
DEF PROCcross(A(),B(),C())
C() = A(1)*B(2)-A(2)*B(1), A(2)*B(0)-A(0)*B(2), A(0)*B(1)-A(1)*B(0)
ENDPROC
DEF FNscalartriple(A(),B(),C())
LOCAL D() : DIM D(2)
PROCcross(B(),C(),D())
= FNdot(A(),D())
DEF PROCvectortriple(A(),B(),C(),D())
PROCcross(B(),C(),D())
PROCcross(A(),D(),D())
ENDPROC |
http://rosettacode.org/wiki/Validate_International_Securities_Identification_Number | Validate International Securities Identification Number | An International Securities Identification Number (ISIN) is a unique international identifier for a financial security such as a stock or bond.
Task
Write a function or program that takes a string as input, and checks whether it is a valid ISIN.
It is only valid if it has the correct format, and the embedded checksum is correct.
Demonstrate that your code passes the test-cases listed below.
Details
The format of an ISIN is as follows:
┌───────────── a 2-character ISO country code (A-Z)
│ ┌─────────── a 9-character security code (A-Z, 0-9)
│ │ ┌── a checksum digit (0-9)
AU0000XVGZA3
For this task, you may assume that any 2-character alphabetic sequence is a valid country code.
The checksum can be validated as follows:
Replace letters with digits, by converting each character from base 36 to base 10, e.g. AU0000XVGZA3 →1030000033311635103.
Perform the Luhn test on this base-10 number.
There is a separate task for this test: Luhn test of credit card numbers.
You don't have to replicate the implementation of this test here ─── you can just call the existing function from that task. (Add a comment stating if you did this.)
Test cases
ISIN
Validity
Comment
US0378331005
valid
US0373831005
not valid
The transposition typo is caught by the checksum constraint.
U50378331005
not valid
The substitution typo is caught by the format constraint.
US03378331005
not valid
The duplication typo is caught by the format constraint.
AU0000XVGZA3
valid
AU0000VXGZA3
valid
Unfortunately, not all transposition typos are caught by the checksum constraint.
FR0000988040
valid
(The comments are just informational. Your function should simply return a Boolean result. See #Raku for a reference solution.)
Related task:
Luhn test of credit card numbers
Also see
Interactive online ISIN validator
Wikipedia article: International Securities Identification Number
| #AWK | AWK |
# syntax: GAWK -f VALIDATE_INTERNATIONAL_SECURITIES_IDENTIFICATION_NUMBER.AWK
# converted from Fortran
BEGIN {
for (i=0; i<=255; i++) { ord_arr[sprintf("%c",i)] = i } # build array[character]=ordinal_value
n = split("US0378331005,US0373831005,U50378331005,US03378331005,AU0000XVGZA3,AU0000VXGZA3,FR0000988040",arr,",")
for (i=1; i<=n; i++) {
printf("%s %s\n",is_isin(arr[i]),arr[i])
}
exit(0)
}
function is_isin(arg, i,j,k,s,v) {
for (i=1; i<=12; i++) { # convert to an array of digits
k = ord_arr[substr(arg,i,1)]
if (k >= 48 && k <= 57) {
if (i < 3) { return(0) }
k -= 48
s[++j] = k
} else if (k >= 65 && k <= 90) {
if (i == 12) { return(0) }
k = k - 65 + 10
s[++j] = int(k / 10)
s[++j] = k % 10
} else {
return(0)
}
}
for (i=j-1; i>=1; i-=2) { # compute checksum
k = 2 * s[i]
if (k > 9) { k -= 9 }
v += k
}
for (i=j; i>=1; i-=2) {
v += s[i]
}
return(v % 10 == 0)
}
|
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #Python | Python |
s = [1, 2, 2, 3, 4, 4, 5]
for i in range(len(s)):
curr = s[i]
if i > 0 and curr == prev:
print(i)
prev = curr
|
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #Raku | Raku | my @s = 1, 2, 2, 3, 4, 4, 5;
loop (my $i = 0; $i < 7; $i += 1) {
my $curr = @s[$i];
my $prev;
if $i > 1 and $curr == $prev {
say $i;
}
$prev = $curr;
} |
http://rosettacode.org/wiki/Variable_declaration_reset | Variable declaration reset | A decidely non-challenging task to highlight a potential difference between programming languages.
Using a straightforward longhand loop as in the JavaScript and Phix examples below, show the locations of elements which are identical to the immediately preceding element in {1,2,2,3,4,4,5}. The (non-blank) results may be 2,5 for zero-based or 3,6 if one-based.
The purpose is to determine whether variable declaration (in block scope) resets the contents on every iteration.
There is no particular judgement of right or wrong here, just a plain-speaking statement of subtle differences.
Should your first attempt bomb with "unassigned variable" exceptions, feel free to code it as (say)
// int prev // crashes with unassigned variable
int prev = -1 // predictably no output
If your programming language does not support block scope (eg assembly) it should be omitted from this task.
| #Red | Red | Red[]
s: [1 2 2 3 4 4 5]
repeat i length? s [
curr: s/:i
if all [i > 1 curr = prev][
print i
]
prev: curr
] |
http://rosettacode.org/wiki/Van_der_Corput_sequence | Van der Corput sequence | When counting integers in binary, if you put a (binary) point to the righEasyLangt of the count then the column immediately to the left denotes a digit with a multiplier of
2
0
{\displaystyle 2^{0}}
; the digit in the next column to the left has a multiplier of
2
1
{\displaystyle 2^{1}}
; and so on.
So in the following table:
0.
1.
10.
11.
...
the binary number "10" is
1
×
2
1
+
0
×
2
0
{\displaystyle 1\times 2^{1}+0\times 2^{0}}
.
You can also have binary digits to the right of the “point”, just as in the decimal number system. In that case, the digit in the place immediately to the right of the point has a weight of
2
−
1
{\displaystyle 2^{-1}}
, or
1
/
2
{\displaystyle 1/2}
.
The weight for the second column to the right of the point is
2
−
2
{\displaystyle 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
. And so on.
If you take the integer binary count of the first table, and reflect the digits about the binary point, you end up with the van der Corput sequence of numbers in base 2.
.0
.1
.01
.11
...
The third member of the sequence, binary 0.01, is therefore
0
×
2
−
1
+
1
×
2
−
2
{\displaystyle 0\times 2^{-1}+1\times 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
.
Distribution of 2500 points each: Van der Corput (top) vs pseudorandom
0
≤
x
<
1
{\displaystyle 0\leq x<1}
Monte Carlo simulations
This sequence is also a superset of the numbers representable by the "fraction" field of an old IEEE floating point standard. In that standard, the "fraction" field represented the fractional part of a binary number beginning with "1." e.g. 1.101001101.
Hint
A hint at a way to generate members of the sequence is to modify a routine used to change the base of an integer:
>>> def base10change(n, base):
digits = []
while n:
n,remainder = divmod(n, base)
digits.insert(0, remainder)
return digits
>>> base10change(11, 2)
[1, 0, 1, 1]
the above showing that 11 in decimal is
1
×
2
3
+
0
×
2
2
+
1
×
2
1
+
1
×
2
0
{\displaystyle 1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+1\times 2^{0}}
.
Reflected this would become .1101 or
1
×
2
−
1
+
1
×
2
−
2
+
0
×
2
−
3
+
1
×
2
−
4
{\displaystyle 1\times 2^{-1}+1\times 2^{-2}+0\times 2^{-3}+1\times 2^{-4}}
Task description
Create a function/method/routine that given n, generates the n'th term of the van der Corput sequence in base 2.
Use the function to compute and display the first ten members of the sequence. (The first member of the sequence is for n=0).
As a stretch goal/extra credit, compute and show members of the sequence for bases other than 2.
See also
The Basic Low Discrepancy Sequences
Non-decimal radices/Convert
Van der Corput sequence
| #AWK | AWK |
# syntax: GAWK -f VAN_DER_CORPUT_SEQUENCE.AWK
# converted from BBC BASIC
BEGIN {
printf("base")
for (i=0; i<=9; i++) {
printf(" %7d",i)
}
printf("\n")
for (base=2; base<=5; base++) {
printf("%-4s",base)
for (i=0; i<=9; i++) {
printf(" %7.5f",vdc(i,base))
}
printf("\n")
}
exit(0)
}
function vdc(n,b, s,v) {
s = 1
while (n) {
s *= b
v += (n % b) / s
n /= b
n = int(n)
}
return(v)
}
|
http://rosettacode.org/wiki/Van_der_Corput_sequence | Van der Corput sequence | When counting integers in binary, if you put a (binary) point to the righEasyLangt of the count then the column immediately to the left denotes a digit with a multiplier of
2
0
{\displaystyle 2^{0}}
; the digit in the next column to the left has a multiplier of
2
1
{\displaystyle 2^{1}}
; and so on.
So in the following table:
0.
1.
10.
11.
...
the binary number "10" is
1
×
2
1
+
0
×
2
0
{\displaystyle 1\times 2^{1}+0\times 2^{0}}
.
You can also have binary digits to the right of the “point”, just as in the decimal number system. In that case, the digit in the place immediately to the right of the point has a weight of
2
−
1
{\displaystyle 2^{-1}}
, or
1
/
2
{\displaystyle 1/2}
.
The weight for the second column to the right of the point is
2
−
2
{\displaystyle 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
. And so on.
If you take the integer binary count of the first table, and reflect the digits about the binary point, you end up with the van der Corput sequence of numbers in base 2.
.0
.1
.01
.11
...
The third member of the sequence, binary 0.01, is therefore
0
×
2
−
1
+
1
×
2
−
2
{\displaystyle 0\times 2^{-1}+1\times 2^{-2}}
or
1
/
4
{\displaystyle 1/4}
.
Distribution of 2500 points each: Van der Corput (top) vs pseudorandom
0
≤
x
<
1
{\displaystyle 0\leq x<1}
Monte Carlo simulations
This sequence is also a superset of the numbers representable by the "fraction" field of an old IEEE floating point standard. In that standard, the "fraction" field represented the fractional part of a binary number beginning with "1." e.g. 1.101001101.
Hint
A hint at a way to generate members of the sequence is to modify a routine used to change the base of an integer:
>>> def base10change(n, base):
digits = []
while n:
n,remainder = divmod(n, base)
digits.insert(0, remainder)
return digits
>>> base10change(11, 2)
[1, 0, 1, 1]
the above showing that 11 in decimal is
1
×
2
3
+
0
×
2
2
+
1
×
2
1
+
1
×
2
0
{\displaystyle 1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+1\times 2^{0}}
.
Reflected this would become .1101 or
1
×
2
−
1
+
1
×
2
−
2
+
0
×
2
−
3
+
1
×
2
−
4
{\displaystyle 1\times 2^{-1}+1\times 2^{-2}+0\times 2^{-3}+1\times 2^{-4}}
Task description
Create a function/method/routine that given n, generates the n'th term of the van der Corput sequence in base 2.
Use the function to compute and display the first ten members of the sequence. (The first member of the sequence is for n=0).
As a stretch goal/extra credit, compute and show members of the sequence for bases other than 2.
See also
The Basic Low Discrepancy Sequences
Non-decimal radices/Convert
Van der Corput sequence
| #BASIC | BASIC | 10 DEFINT A-Z
20 FOR B=2 TO 5
30 PRINT USING "BASE #:";B;
40 FOR I=0 TO 9
50 P=0: Q=1: N=I
60 IF N=0 GOTO 110
70 P=P*B+N MOD B
80 Q=Q*B
90 N=N\B
100 GOTO 60
110 X=P: Y=Q
120 IF P=0 GOTO 150
130 N=P: P=Q MOD P: Q=N
140 GOTO 120
150 X=X\Q
160 Y=Y\Q
170 IF X=0 THEN PRINT " 0"; ELSE PRINT USING " ##/##";X;Y;
180 NEXT I
190 PRINT
200 NEXT B |
http://rosettacode.org/wiki/Variables | Variables | Task
Demonstrate a language's methods of:
variable declaration
initialization
assignment
datatypes
scope
referencing, and
other variable related facilities
| #ALGOL_68 | ALGOL 68 | int j; |
http://rosettacode.org/wiki/Variables | Variables | Task
Demonstrate a language's methods of:
variable declaration
initialization
assignment
datatypes
scope
referencing, and
other variable related facilities
| #ALGOL_W | ALGOL W | % declare some variables %
integer a1, a2; real b; long real c; complex d; long complex f;
logical g; bits h; string(32) j;
% assign "initial values" %
f := d := c := b := a2 := a1 := 0; % multiple assignment %
g := false; h := #a0; j := "Hello, World!";
|
http://rosettacode.org/wiki/Van_Eck_sequence | Van Eck sequence | The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occured previously.
Example
Using A:
0
Using B:
0 0
Using C:
0 0 1
Using B:
0 0 1 0
Using C: (zero last occurred two steps back - before the one)
0 0 1 0 2
Using B:
0 0 1 0 2 0
Using C: (two last occurred two steps back - before the zero)
0 0 1 0 2 0 2 2
Using C: (two last occurred one step back)
0 0 1 0 2 0 2 2 1
Using C: (one last appeared six steps back)
0 0 1 0 2 0 2 2 1 6
...
Task
Create a function/procedure/method/subroutine/... to generate the Van Eck sequence of numbers.
Use it to display here, on this page:
The first ten terms of the sequence.
Terms 991 - to - 1000 of the sequence.
References
Don't Know (the Van Eck Sequence) - Numberphile video.
Wikipedia Article: Van Eck's Sequence.
OEIS sequence: A181391.
| #APL | APL | (10∘↑,[.5]¯10∘↑)(⊢,(⊃∘⌽∊¯1∘↓)∧(1↓⌽)⍳⊃∘⌽)⍣999⊢,0 |
http://rosettacode.org/wiki/Van_Eck_sequence | Van Eck sequence | The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occured previously.
Example
Using A:
0
Using B:
0 0
Using C:
0 0 1
Using B:
0 0 1 0
Using C: (zero last occurred two steps back - before the one)
0 0 1 0 2
Using B:
0 0 1 0 2 0
Using C: (two last occurred two steps back - before the zero)
0 0 1 0 2 0 2 2
Using C: (two last occurred one step back)
0 0 1 0 2 0 2 2 1
Using C: (one last appeared six steps back)
0 0 1 0 2 0 2 2 1 6
...
Task
Create a function/procedure/method/subroutine/... to generate the Van Eck sequence of numbers.
Use it to display here, on this page:
The first ten terms of the sequence.
Terms 991 - to - 1000 of the sequence.
References
Don't Know (the Van Eck Sequence) - Numberphile video.
Wikipedia Article: Van Eck's Sequence.
OEIS sequence: A181391.
| #AppleScript | AppleScript | use AppleScript version "2.4"
use scripting additions
-- vanEck :: Int -> [Int]
on vanEck(n)
-- First n terms of the vanEck sequence.
script go
on |λ|(xns, i)
set {x, ns} to xns
set prev to item (1 + x) of ns
if 0 ≠ prev then
set v to i - prev
else
set v to 0
end if
{{v, insert(ns, x, i)}, v}
end |λ|
end script
{0} & item 2 of mapAccumL(go, ¬
{0, replicate(n, 0)}, enumFromTo(1, n - 1))
end vanEck
--------------------------- TEST ---------------------------
on run
unlines({¬
"First 10 terms:", ¬
showList(vanEck(10)), ¬
"", ¬
"Terms 990 to 1000:", ¬
showList(items -10 thru -1 of vanEck(1000))})
end run
------------------------- GENERIC --------------------------
-- enumFromTo :: Int -> Int -> [Int]
on enumFromTo(m, n)
if m ≤ n then
set lst to {}
repeat with i from m to n
set end of lst to i
end repeat
lst
else
{}
end if
end enumFromTo
-- foldl :: (a -> b -> a) -> a -> [b] -> a
on foldl(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to |λ|(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldl
-- insert :: [Int] -> Int -> Int -> [Int]
on insert(xs, i, v)
-- A list updated at position i with value v.
set item (1 + i) of xs to v
xs
end insert
-- intercalate :: String -> [String] -> String
on intercalate(delim, xs)
set {dlm, my text item delimiters} to ¬
{my text item delimiters, delim}
set s to xs as text
set my text item delimiters to dlm
s
end intercalate
-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
-- The list obtained by applying f
-- to each element of xs.
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map
-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
-- 2nd class handler function lifted into 1st class script wrapper.
if script is class of f then
f
else
script
property |λ| : f
end script
end if
end mReturn
-- 'The mapAccumL function behaves like a combination of map and foldl;
-- it applies a function to each element of a list, passing an
-- accumulating parameter from |Left| to |Right|, and returning a final
-- value of this accumulator together with the new list.' (see Hoogle)
-- mapAccumL :: (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y])
on mapAccumL(f, acc, xs)
script
on |λ|(a, x, i)
tell mReturn(f) to set pair to |λ|(item 1 of a, x, i)
{item 1 of pair, (item 2 of a) & {item 2 of pair}}
end |λ|
end script
foldl(result, {acc, []}, xs)
end mapAccumL
-- Egyptian multiplication - progressively doubling a list, appending
-- stages of doubling to an accumulator where needed for binary
-- assembly of a target length
-- replicate :: Int -> a -> [a]
on replicate(n, a)
set out to {}
if 1 > n then return out
set dbl to {a}
repeat while (1 < n)
if 0 < (n mod 2) then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate
-- showList :: [a] -> String
on showList(xs)
"[" & intercalate(", ", map(my str, xs)) & "]"
end showList
-- str :: a -> String
on str(x)
x as string
end str
-- unlines :: [String] -> String
on unlines(xs)
-- A single string formed by the intercalation
-- of a list of strings with the newline character.
set {dlm, my text item delimiters} to ¬
{my text item delimiters, linefeed}
set s to xs as text
set my text item delimiters to dlm
s
end unlines |
http://rosettacode.org/wiki/Vampire_number | Vampire number | A vampire number is a natural decimal number with an even number of digits, that can be factored into two integers.
These two factors are called the fangs, and must have the following properties:
they each contain half the number of the decimal digits of the original number
together they consist of exactly the same decimal digits as the original number
at most one of them has a trailing zero
An example of a vampire number and its fangs: 1260 : (21, 60)
Task
Print the first 25 vampire numbers and their fangs.
Check if the following numbers are vampire numbers and, if so, print them and their fangs:
16758243290880, 24959017348650, 14593825548650
Note that a vampire number can have more than one pair of fangs.
See also
numberphile.com.
vampire search algorithm
vampire numbers on OEIS
| #Clojure | Clojure | (defn factor-pairs [n]
(for [x (range 2 (Math/sqrt n))
:when (zero? (mod n x))]
[x (quot n x)]))
(defn fangs [n]
(let [dlen (comp count str)
half (/ (dlen n) 2)
halves? #(apply = (cons half (map dlen %)))
digits #(sort (apply str %))]
(filter #(and (halves? %)
(= (sort (str n)) (digits %)))
(factor-pairs n))))
(defn vampiric? [n]
(let [fangs (fangs n)]
(if (empty? fangs) nil [n fangs])))
(doseq [n (take 25 (keep vampiric? (range)))]
(prn n))
(doseq [n [16758243290880, 24959017348650, 14593825548650]]
(println (or (vampiric? n) (str n " is not vampiric.")))) |
http://rosettacode.org/wiki/Variable-length_quantity | Variable-length quantity | Implement some operations on variable-length quantities, at least including conversions from a normal number in the language to the binary representation of the variable-length quantity for that number, and vice versa. Any variants are acceptable.
Task
With above operations,
convert these two numbers 0x200000 (2097152 in decimal) and 0x1fffff (2097151 in decimal) into sequences of octets (an eight-bit byte);
display these sequences of octets;
convert these sequences of octets back to numbers, and check that they are equal to original numbers.
| #Racket | Racket |
#lang racket
(define (try n)
(printf "Original number: ~s (0x~x)\n" n n)
(define 4octets (integer->integer-bytes n 4 #f))
(printf "Octets: ~a (byte-string: ~s)\n"
(string-join (map (λ(o) (~r o #:base 16))
(bytes->list 4octets))
":")
4octets)
(define m (integer-bytes->integer 4octets #f))
(printf "Back to a number: ~s (~a)\n"
m (if (= m n) "OK" "BAD")))
(for-each try '(#x200000 #x1fffff))
|
http://rosettacode.org/wiki/Variable-length_quantity | Variable-length quantity | Implement some operations on variable-length quantities, at least including conversions from a normal number in the language to the binary representation of the variable-length quantity for that number, and vice versa. Any variants are acceptable.
Task
With above operations,
convert these two numbers 0x200000 (2097152 in decimal) and 0x1fffff (2097151 in decimal) into sequences of octets (an eight-bit byte);
display these sequences of octets;
convert these sequences of octets back to numbers, and check that they are equal to original numbers.
| #Raku | Raku | sub vlq_encode ($number is copy) {
my $string = '';
my $t = 0x7F +& $number;
$number +>= 7;
$string = $t.chr ~ $string;
while ($number) {
$t = 0x7F +& $number;
$string = (0x80 +| $t).chr ~ $string;
$number +>= 7;
}
return $string;
}
sub vlq_decode ($string is copy) {
my $number = '0b';
for $string.ords -> $oct {
$number ~= ($oct +& 0x7F).fmt("%07b");
}
return :2($number);
}
#test encoding and decoding
for (
0, 0xa, 123, 254, 255, 256,
257, 65534, 65535, 65536, 65537, 0x1fffff,
0x200000
) -> $testcase {
my $encoded = vlq_encode($testcase);
printf "%8s %12s %8s\n", $testcase,
( join ':', $encoded.ords>>.fmt("%02X") ),
vlq_decode($encoded);
} |
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function
| #Elena | Elena | import system'routines;
import extensions;
extension variadicOp
{
printAll(params object[] list)
{
for(int i := 0, i < list.Length, i+=1)
{
self.printLine(list[i])
}
}
}
public program()
{
console.printAll("test", "rosetta code", 123, 5.6r)
} |
http://rosettacode.org/wiki/Variadic_function | Variadic function | Task
Create a function which takes in a variable number of arguments and prints each one on its own line.
Also show, if possible in your language, how to call the function on a list of arguments constructed at runtime.
Functions of this type are also known as Variadic Functions.
Related task
Call a function
| #Elixir | Elixir | defmodule RC do
def print_each( arguments ) do
Enum.each(arguments, fn x -> IO.inspect x end)
end
end
RC.print_each([1,2,3])
RC.print_each(["Mary", "had", "a", "little", "lamb"]) |
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Haskell | Haskell | import Foreign
sizeOf (undefined :: Int) -- size of Int in bytes (4 on mine)
sizeOf (undefined :: Double) -- size of Double in bytes (8 on mine)
sizeOf (undefined :: Bool) -- size of Bool in bytes (4 on mine)
sizeOf (undefined :: Ptr a) -- size of Ptr in bytes (4 on mine) |
http://rosettacode.org/wiki/Variable_size/Get | Variable size/Get | Demonstrate how to get the size of a variable.
See also: Host introspection
| #Icon_and_Unicon | Icon and Unicon | record rec0()
record rec4(a,b,c,d)
procedure main() # get size
every i := seq(1) do {
a0 := &allocated
x := case i of {
1 : "ABCDEFGH"
2 : reverse(x)
10 : &digits
11 : x--x
20 : []
21 : [1,2]
22 : [1,2,3]
30 : set()
31 : set("X")
32 : set("A","B")
40 : table(1)
50 : rec0()
51 : rec4()
60 : create seq(1)
99 : break
default : next
}
a1 := &allocated
write("type=",type(x)," *x=",*x," bytes allocated=",a1-a0)
}
end |
http://rosettacode.org/wiki/Vector | Vector | Task
Implement a Vector class (or a set of functions) that models a Physical Vector. The four basic operations and a pretty print function should be implemented.
The Vector may be initialized in any reasonable way.
Start and end points, and direction
Angular coefficient and value (length)
The four operations to be implemented are:
Vector + Vector addition
Vector - Vector subtraction
Vector * scalar multiplication
Vector / scalar division
| #Maple | Maple | module MyVector()
option object;
local value := Vector();
export ModuleApply::static := proc( )
Object( MyVector, _passed );
end proc;
export ModuleCopy::static := proc( mv::MyVector, proto::MyVector, v::Vector, $ )
mv:-value := v;
end proc;
export ModulePrint::static := proc(mv::MyVector, $ )
mv:-value;
end proc;
# operations:
export `+`::static := proc( v1::MyVector, v2::MyVector )
MyVector( v1:-value + v2:-value );
end proc;
export `*`::static := proc( v::MyVector, scalar_val::numeric)
MyVector( v:-value * scalar_val);
end proc;
end module: |
http://rosettacode.org/wiki/Vector | Vector | Task
Implement a Vector class (or a set of functions) that models a Physical Vector. The four basic operations and a pretty print function should be implemented.
The Vector may be initialized in any reasonable way.
Start and end points, and direction
Angular coefficient and value (length)
The four operations to be implemented are:
Vector + Vector addition
Vector - Vector subtraction
Vector * scalar multiplication
Vector / scalar division
| #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | ClearAll[vector,PrintVector]
vector[{r_,\[Theta]_}]:=vector@@AngleVector[{r,\[Theta]}]
vector[x_,y_]+vector[w_,z_]^:=vector[x+w,y+z]
a_ vector[x_,y_]^:=vector[a x,a y]
vector[x_,y_]-vector[w_,z_]^:=vector[x-w,y-z]
PrintVector[vector[x_,y_]]:=Print["vector has first component: ",x," And second component: ",y]
vector[1,2]+vector[3,4]
vector[1,2]-vector[3,4]
12vector[1,2]
vector[1,2]/3
PrintVector@vector[{Sqrt[2],45Degree}] |
http://rosettacode.org/wiki/Verify_distribution_uniformity/Chi-squared_test | Verify distribution uniformity/Chi-squared test | Task
Write a function to verify that a given distribution of values is uniform by using the
χ
2
{\displaystyle \chi ^{2}}
test to see if the distribution has a likelihood of happening of at least the significance level (conventionally 5%).
The function should return a boolean that is true if the distribution is one that a uniform distribution (with appropriate number of degrees of freedom) may be expected to produce.
Reference
an entry at the MathWorld website: chi-squared distribution.
| #zkl | zkl | /* Numerical integration method */
fcn Simpson3_8(f,a,b,N){ // fcn,double,double,Int --> double
h,h1:=(b - a)/N, h/3.0;
h*[1..3*N - 1].reduce('wrap(sum,j){
l1:=(if(j%3) 3.0 else 2.0);
sum + l1*f(a + h1*j);
},f(a) + f(b))/8.0;
}
const A=12;
fcn Gamma_Spouge(z){ // double --> double
var coefs=fcn{ // this runs only once, at construction time
a,coefs:=A.toFloat(),(A).pump(List(),0.0);
k1_factrl:=1.0;
coefs[0]=(2.0*(0.0).pi).sqrt();
foreach k in ([1.0..A-1]){
coefs[k]=(a - k).exp() * (a - k).pow(k - 0.5) / k1_factrl;
k1_factrl*=-k;
}
coefs
}();
( [1..A-1].reduce('wrap(accum,k){ accum + coefs[k]/(z + k) },coefs[0])
* (-(z + A)).exp()*(z + A).pow(z + 0.5) )
/ z;
}
fcn f0(t,aa1){ t.pow(aa1)*(-t).exp() }
fcn GammaIncomplete_Q(a,x){ // double,double --> double
h:=1.5e-2; /* approximate integration step size */
/* this cuts off the tail of the integration to speed things up */
y:=a - 1; f:=f0.fp1(y);
while((f(y)*(x - y)>2.0e-8) and (y<x)){ y+=0.4; }
if(y>x) y=x;
1.0 - Simpson3_8(f,0.0,y,(y/h).toInt())/Gamma_Spouge(a);
} |
http://rosettacode.org/wiki/Vigen%C3%A8re_cipher | Vigenère cipher | Task
Implement a Vigenère cypher, both encryption and decryption.
The program should handle keys and text of unequal length,
and should capitalize everything and discard non-alphabetic characters.
(If your program handles non-alphabetic characters in another way,
make a note of it.)
Related tasks
Caesar cipher
Rot-13
Substitution Cipher
| #Nim | Nim | import strutils
proc encrypt(msg, key: string): string =
var pos = 0
for c in msg:
if c in Letters:
result.add chr(((ord(key[pos]) + ord(c.toUpperAscii)) mod 26) + ord('A'))
pos = (pos + 1) mod key.len
proc decrypt(msg, key: string): string =
var pos = 0
for c in msg:
result.add chr(((26 + ord(c) - ord(key[pos])) mod 26) + ord('A'))
pos = (pos + 1) mod key.len
const text = "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!"
const key = "VIGENERECIPHER"
let encr = encrypt(text, key)
let decr = decrypt(encr, key)
echo text
echo encr
echo decr |
http://rosettacode.org/wiki/Vigen%C3%A8re_cipher | Vigenère cipher | Task
Implement a Vigenère cypher, both encryption and decryption.
The program should handle keys and text of unequal length,
and should capitalize everything and discard non-alphabetic characters.
(If your program handles non-alphabetic characters in another way,
make a note of it.)
Related tasks
Caesar cipher
Rot-13
Substitution Cipher
| #Objeck | Objeck |
bundle Default {
class VigenereCipher {
function : Main(args : String[]) ~ Nil {
key := "VIGENERECIPHER";
ori := "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!";
enc := encrypt(ori, key);
IO.Console->Print("encrypt: ")->PrintLine(enc);
IO.Console->Print("decrypt: ")->PrintLine(decrypt(enc, key));
}
function : native : encrypt(text : String, key : String) ~ String {
res := "";
text := text->ToUpper();
j := 0;
each(i : text) {
c := text->Get(i);
if(c >= 'A' & c <= 'Z') {
res->Append(((c + key->Get(j) - 2 * 'A') % 26 + 'A')->As(Char));
j += 1;
j := j % key->Size();
};
};
return res;
}
function : native : decrypt(text : String, key : String) ~ String {
res := "";
text := text->ToUpper();
j := 0;
each(i : text) {
c := text->Get(i);
if(c >= 'A' & c <= 'Z') {
res->Append(((c - key->Get(j) + 26) % 26 + 'A')->As(Char));
j += 1;
j := j % key->Size();
};
};
return res;
}
}
}
|
http://rosettacode.org/wiki/Visualize_a_tree | Visualize a tree | A tree structure (i.e. a rooted, connected acyclic graph) is often used in programming.
It's often helpful to visually examine such a structure.
There are many ways to represent trees to a reader, such as:
indented text (à la unix tree command)
nested HTML tables
hierarchical GUI widgets
2D or 3D images
etc.
Task
Write a program to produce a visual representation of some tree.
The content of the tree doesn't matter, nor does the output format, the only requirement being that the output is human friendly.
Make do with the vague term "friendly" the best you can.
| #Wren | Wren | import "/dynamic" for Struct
import "random" for Random
var Stem = Struct.create("Stem", ["str", "next"])
var SDOWN = " |"
var SLAST = " `"
var SNONE = " "
var rand = Random.new()
var tree // recursive
tree = Fn.new { |root, head|
var col = Stem.new(null, null)
var tail = head
while (tail) {
System.write(tail.str)
if (!tail.next) break
tail = tail.next
}
System.print("--%(root)")
if (root <= 1) return
if (tail && tail.str == SLAST) tail.str = SNONE
if (!tail) {
tail = head = col
} else {
tail.next = col
}
while (root != 0) { // make a tree by doing something random
var r = 1 + rand.int(root)
root = root - r
col.str = (root != 0) ? SDOWN : SLAST
tree.call(r, head)
}
tail.next = null
}
var n = 8
tree.call(n, null) |
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively (read a single directory).
| #Rascal | Rascal | //usage example: To list just Rascal source files, Walk(|home:///workspace/|, ".rsc");
module Walk
import String;
import IO;
public void Walk(loc a, str pattern){
for (entry <- listEntries(a))
if (endsWith(entry, pattern))
println(entry);
elseif (isDirectory(a+entry))
Walk(a+entry, pattern);
} |
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively (read a single directory).
| #REALbasic | REALbasic | Sub printFiles(parentDir As FolderItem, pattern As String)
For i As Integer = 1 To parentDir.Count
If parentDir.Item(i).Directory Then
printFiles(parentDir.Item(i), pattern)
Else
Dim rg as New RegEx
Dim myMatch as RegExMatch
rg.SearchPattern = pattern
myMatch = rg.search(parentDir.Item(i).Name)
If myMatch <> Nil Then Print(parentDir.Item(i).AbsolutePath)
End If
Next
End Sub |
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