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http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Comal | Comal | PROC Recursive(n) CLOSED
r:=1
IF n>1 THEN
r:=n*Recursive(n-1)
ENDIF
RETURN r
ENDPROC Recursive |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Vim_Script | Vim Script | for i in range(1, 100)
if i % 15 == 0
echo "FizzBuzz"
elseif i % 5 == 0
echo "Buzz"
elseif i % 3 == 0
echo "Fizz"
else
echo i
endif
endfor |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Modula-3 | Modula-3 | // nanoquery has no function to get just a character
// so we have to implement our own
def get_char()
c = ""
while len(c)=0
c = input()
end
return c[0]
end
// a function to handle fatal errors
def fatal_error(errtext)
println "%" + errtext
println "usage: " + args[1] + " [filename.bf]"
exit
end
// get a filename from the command line and read the file in
fname = null
source = null
try
fname = args[2]
source = new(Nanoquery.IO.File, fname).readAll()
catch
fatal_error("error while trying to read from specified file")
end
// start with one hundred cells and the pointer at 0
cells = {0} * 100
ptr = 0
// loop through the instructions
loc = 0
while loc < len(source)
instr = source[loc]
if instr = ">"
ptr += 1
if ptr = len(cells)
cells.append(0)
end
else if instr = "<"
ptr -= 1
if ptr < 0
ptr = 0
end
else if instr = "+"
cells[ptr] += 1
else if instr = "-"
cells[ptr] -= 1
else if instr = "."
print chr(cells[ptr])
else if instr = ","
cells[ptr] = ord(get_char())
else if instr = "["
if cells[ptr] = 0
while source[loc] != "]"
loc += 1
end
end
else if instr = "]"
if cells[ptr] != 0
while source[loc] != "["
loc -= 1
end
end
else
// do nothing
end
loc += 1
end |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Octave | Octave | global target;
target = split("METHINKS IT IS LIKE A WEASEL", "");
charset = ["A":"Z", " "];
p = ones(length(charset), 1) ./ length(charset);
parent = discrete_rnd(charset, p, length(target), 1);
mutaterate = 0.1;
C = 1000;
function r = fitness(parent, target)
r = sum(parent == target) ./ length(target);
endfunction
function r = mutate(parent, mutaterate, charset)
r = parent;
p = unifrnd(0, 1, length(parent), 1);
nmutants = sum( p < mutaterate );
if (nmutants)
s = discrete_rnd(charset, ones(length(charset), 1) ./ length(charset),nmutants,1);
r( p < mutaterate ) = s;
endif
endfunction
function r = evolve(parent, mutatefunc, fitnessfunc, C, mutaterate, charset)
global target;
children = [];
for i = 1:C
children = [children, mutatefunc(parent, mutaterate, charset)];
endfor
children = [parent, children];
fitval = [];
for i = 1:columns(children)
fitval = [fitval, fitnessfunc(children(:,i), target)];
endfor
[m, im] = max(fitval);
r = children(:, im);
endfunction
function printgen(p, t, i)
printf("%3d %5.2f %s\n", i, fitness(p, t), p');
endfunction
i = 0;
while( !all(parent == target) )
i++;
parent = evolve(parent, @mutate, @fitness, C, mutaterate, charset);
if ( mod(i, 1) == 0 )
printgen(parent, target, i);
endif
endwhile
disp(parent');
|
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #NESL | NESL | function fib(n) = if n < 2 then n else fib(n - 2) + fib(n - 1); |
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #Visual_Basic_.NET | Visual Basic .NET | Module System_Command
Sub Main()
Dim cmd As New Process
cmd.StartInfo.FileName = "cmd.exe"
cmd.StartInfo.RedirectStandardInput = True
cmd.StartInfo.RedirectStandardOutput = True
cmd.StartInfo.CreateNoWindow = True
cmd.StartInfo.UseShellExecute = False
cmd.Start()
cmd.StandardInput.WriteLine("dir")
cmd.StandardInput.Flush()
cmd.StandardInput.Close()
Console.WriteLine(cmd.StandardOutput.ReadToEnd)
End Sub
End Module
|
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #Wart | Wart | system "ls" |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Comefrom0x10 | Comefrom0x10 | n = 5 # calculates n!
acc = 1
factorial
comefrom
comefrom accumulate if n < 1
accumulate
comefrom factorial
acc = acc * n
comefrom factorial if n is 0
n = n - 1
acc # prints the result |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Visual_Basic_.NET | Visual Basic .NET |
implement main
open core, console
class predicates
fizzbuzz : (integer) -> string procedure (i).
clauses
fizzbuzz(X) = S :- X mod 15 = 0, S = "FizzBuzz", !.
fizzbuzz(X) = S :- X mod 5 = 0, S = "Buzz", !.
fizzbuzz(X) = S :- X mod 3 = 0, S = "Fizz", !.
fizzbuzz(X) = S :- S = toString(X).
run() :-
foreach X = std::fromTo(1,100) do
write(fizzbuzz(X)), write("\n")
end foreach,
succeed.
end implement main
goal
console::runUtf8(main::run).
|
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Nanoquery | Nanoquery | // nanoquery has no function to get just a character
// so we have to implement our own
def get_char()
c = ""
while len(c)=0
c = input()
end
return c[0]
end
// a function to handle fatal errors
def fatal_error(errtext)
println "%" + errtext
println "usage: " + args[1] + " [filename.bf]"
exit
end
// get a filename from the command line and read the file in
fname = null
source = null
try
fname = args[2]
source = new(Nanoquery.IO.File, fname).readAll()
catch
fatal_error("error while trying to read from specified file")
end
// start with one hundred cells and the pointer at 0
cells = {0} * 100
ptr = 0
// loop through the instructions
loc = 0
while loc < len(source)
instr = source[loc]
if instr = ">"
ptr += 1
if ptr = len(cells)
cells.append(0)
end
else if instr = "<"
ptr -= 1
if ptr < 0
ptr = 0
end
else if instr = "+"
cells[ptr] += 1
else if instr = "-"
cells[ptr] -= 1
else if instr = "."
print chr(cells[ptr])
else if instr = ","
cells[ptr] = ord(get_char())
else if instr = "["
if cells[ptr] = 0
while source[loc] != "]"
loc += 1
end
end
else if instr = "]"
if cells[ptr] != 0
while source[loc] != "["
loc -= 1
end
end
else
// do nothing
end
loc += 1
end |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Oforth | Oforth | 200 Constant new: C
5 Constant new: RATE
: randChar // -- c
27 rand dup 27 == ifTrue: [ drop ' ' ] else: [ 'A' + 1- ] ;
: fitness(a b -- n)
a b zipWith(#==) sum ;
: mutate(s -- s')
s map(#[ 100 rand RATE <= ifTrue: [ drop randChar ] ]) charsAsString ;
: evolve(target)
| parent |
ListBuffer init(target size, #randChar) charsAsString ->parent
1 while ( parent target <> ) [
ListBuffer init(C, #[ parent mutate ]) dup add(parent)
maxFor(#[ target fitness ]) dup ->parent . dup println 1+
] drop ; |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref savelog symbols
numeric digits 210000 /*prepare for some big 'uns. */
parse arg x y . /*allow a single number or range.*/
if x == '' then do /*no input? Then assume -30-->+30*/
x = -30
y = -x
end
if y == '' then y = x /*if only one number, show fib(n)*/
loop k = x to y /*process each Fibonacci request.*/
q = fib(k)
w = q.length /*if wider than 25 bytes, tell it*/
say 'Fibonacci' k"="q
if w > 25 then say 'Fibonacci' k "has a length of" w
end k
exit
/*-------------------------------------FIB subroutine (non-recursive)---*/
method fib(arg) private static
parse arg n
na = n.abs
if na < 2 then return na /*handle special cases. */
a = 0
b = 1
loop j = 2 to na
s = a + b
a = b
b = s
end j
if n > 0 | na // 2 == 1 then return s /*if positive or odd negative... */
else return -s /*return a negative Fib number. */
|
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #Wren | Wren | /* run_system_command.wren */
class Command {
foreign static exec(name, param) // the code for this is provided by Go
}
Command.exec("ls", "-lt")
System.print()
Command.exec("dir", "") |
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #x86_Assembly | x86 Assembly |
; Executes '/bin/ls'
; Build with:
; nasm -felf32 execls.asm
; ld -m elf_i386 execls.o -o execls
global _start
section .text
_start:
mov eax, 0x0B ; sys_execve(char *str, char **args, char **envp)
mov ebx, .path ; pathname
push DWORD 0
push DWORD .path
lea ecx, [esp] ; arguments [pathname]
xor edx, edx ; environment variables []
int 0x80 ; syscall
.path:
db '/bin/ls', 0x00
|
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Common_Lisp | Common Lisp | (defun factorial (n)
(if (zerop n) 1 (* n (factorial (1- n))))) |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Visual_Prolog | Visual Prolog |
implement main
open core, console
class predicates
fizzbuzz : (integer) -> string procedure (i).
clauses
fizzbuzz(X) = S :- X mod 15 = 0, S = "FizzBuzz", !.
fizzbuzz(X) = S :- X mod 5 = 0, S = "Buzz", !.
fizzbuzz(X) = S :- X mod 3 = 0, S = "Fizz", !.
fizzbuzz(X) = S :- S = toString(X).
run() :-
foreach X = std::fromTo(1,100) do
write(fizzbuzz(X)), write("\n")
end foreach,
succeed.
end implement main
goal
console::runUtf8(main::run).
|
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Never | Never |
record BFI
{
cmd : char;
next : BFI;
jmp : BFI;
}
record MEM
{
val : int;
next : MEM;
prev : MEM;
}
func compile(prog : string) -> BFI
{
var i = 0;
var n = BFI;
var p = BFI;
var j = BFI;
var pgm = BFI;
for (i = 0; i < length(prog); i = i + 1) {
n = BFI('0', nil, nil);
if (p != nil) {
p.next = n
} else {
pgm = n
};
n.cmd = prog[i];
p = n;
if (prog[i] == '[') {
n.jmp = j;
j = n;
0
} else if (prog[i] == ']') {
n.jmp = j;
j = j.jmp;
n.jmp.jmp = n;
0
} else {
0
}
};
pgm
}
func exec(pgm : BFI) -> int
{
var m = MEM(0, nil, nil);
var n = BFI;
for (n = pgm; n != nil; n = n.next) {
if (n.cmd == '+') {
m.val = m.val + 1
} else if (n.cmd == '-') {
m.val = m.val - 1
} else if (n.cmd == '.') {
printc(chr(m.val));
0
} else if (n.cmd == ',') {
m.val = read()
} else if (n.cmd == '[') {
if (m.val == 0) {
n = n.jmp;
0
} else {
0
}
} else if (n.cmd == ']') {
if (m.val != 0) {
n = n.jmp;
0
} else {
0
}
} else if (n.cmd == '<') {
m = m.prev;
0
} else if (n.cmd == '>') {
if (m.next == nil) {
m.next = MEM(0, nil, nil);
m.next.prev = m;
0
} else {
0
};
m = m.next;
0
} else {
0
}
};
0
}
func run(prog : string) -> int
{
var pgm = BFI;
pgm = compile(prog);
exec(pgm);
0
}
func main() -> int
{
/* Hello World! */
run("++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.");
0
}
|
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #OoRexx | OoRexx |
/* Weasel.rex - Me thinks thou art a weasel. - G,M.D. - 2/25/2011 */
arg C M
/* C is the number of children parent produces each generation. */
/* M is the mutation rate of each gene (character) */
call initialize
generation = 0
do until parent = target
most_fitness = fitness(parent)
most_fit = parent
do C
child = mutate(parent, M)
child_fitness = fitness(child)
if child_fitness > most_fitness then
do
most_fitness = child_fitness
most_fit = child
say "Generation" generation": most fit='"most_fit"', fitness="left(most_fitness,4)
end
end
parent = most_fit
generation = generation + 1
end
exit
initialize:
target = "METHINKS IT IS LIKE A WEASEL"
alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ "
c_length_target = length(target)
parent = mutate(copies(" ", c_length_target), 1.0)
do i = 1 to c_length_target
target_ch.i = substr(target,i,1)
end
return
fitness: procedure expose target_ch. c_length_target
arg parm_string
fitness = 0
do i_target = 1 to c_length_target
if substr(parm_string,i_target,1) = target_ch.i_target then
fitness = fitness + 1
end
return fitness
mutate:procedure expose alphabet
arg string, parm_mutation_rate
result = ""
do istr = 1 to length(string)
if random(1,1000)/1000 <= parm_mutation_rate then
result = result || substr(alphabet,random(1,length(alphabet)),1)
else
result = result || substr(string,istr,1)
end
return result
|
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #NewLISP | NewLISP | (define (fibonacci n)
(let (L '(0 1))
(dotimes (i n)
(setq L (list (L 1) (apply + L))))
(L 1)) )
|
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #Yabasic | Yabasic | system("dir")
//It will return the exit code of the command; its output (if any) will be lost.
print system$("dir")
//Returns the output as a large string. |
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #zkl | zkl | System.cmd(System.isWindows and "dir" or "ls") |
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #ZX_Spectrum_Basic | ZX Spectrum Basic | PAUSE 100 |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Computer.2Fzero_Assembly | Computer/zero Assembly | LDA x
BRZ done_i ; 0! = 1
STA i
loop_i: LDA fact
STA n
LDA i
SUB one
BRZ done_i
STA j
loop_j: LDA fact
ADD n
STA fact
LDA j
SUB one
BRZ done_j
STA j
JMP loop_j
done_j: LDA i
SUB one
STA i
JMP loop_i
done_i: LDA fact
STP
one: 1
fact: 1
i: 0
j: 0
n: 0
x: 5 |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Vlang | Vlang | const (
fizz = Tuple{true, false}
buzz = Tuple{false, true}
fizzbuzz = Tuple{true, true}
)
struct Tuple{
val1 bool
val2 bool
}
fn fizz_or_buzz( val int ) Tuple {
return Tuple{ val % 3 == 0, val % 5 == 0 }
}
fn fizzbuzz( n int ) {
for i in 1..(n + 1) {
match fizz_or_buzz(i) {
fizz { println('Fizz') }
buzz { println('Buzz') }
fizzbuzz { println('FizzBuzz') }
else { println(i) }
}
}
}
fn main(){
fizzbuzz(15)
}
|
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #NewLISP | NewLISP |
; This module translates a string containing a
; Brainf*** program into a list of NewLISP expressions.
; Attempts to optimize consecutive +, -, > and < operations
; as well as bracket loops.
; Create a namespace and put the following definitions in it
(context 'BF)
; If BF:quiet is true, BF:run will return the output of the
; Brainf*** program
(define quiet)
; If BF:show-timing is true, the amount of milliseconds spent
; in 'compiling' (actually translating) and running the
; resulting program will be shown
(define show-timing true)
; The Brainf*** program as a string of characters
(define src "")
; Checks for correct pairs of brackets
(define (well-formed?)
(let (p 0)
(dostring (i src (> 0 p))
(case i
("[" (++ p))
("]" (-- p))))
(zero? p)))
; Translate the Brainf*** command into S-expressions
(define (_compile)
(let ((prog '())
; Translate +
(incr '(++ (tape i) n))
; Translate -
(decr '(-- (tape i) n))
; Translate .
(emit (if quiet
'(push (char (tape i)) result -1)
'(print (char (tape i)))))
; Translate ,
(store '(setf (tape i) (read-key)))
; Check for loop condition
(over? '(zero? (tape i)))
; Current character of the program
(m)
; Find how many times the same character occurs
(rep (fn ((n 1))
(while (= m (src 0))
(++ n)
(pop src))
n)))
; Traverse the program and translate recursively
(until (or (empty? src) (= "]" (setq m (pop src))))
(case m
(">" (push (list '++ 'i (rep)) prog -1))
("<" (push (list '-- 'i (rep)) prog -1))
("+" (push (expand incr '((n (rep))) true) prog -1))
("-" (push (expand decr '((n (rep))) true) prog -1))
("." (push emit prog -1))
("," (push store prog -1))
("[" (push (append (list 'until over?)
(_compile))
prog -1))))
prog))
(define (compile str , tim code)
(setq src (join
(filter (fn (x)
(member x '("<" ">" "-" "+"
"." "," {[} {]})))
(explode str))))
; Throw an error if the program is ill-formed
(unless (well-formed?)
(throw-error "Unbalanced brackets in Brainf*** source string"))
(setq tim (time (setq code (cons 'begin (_compile)))))
(and show-timing (println "Compilation time: " tim))
code)
; Translate and run
; Tape size is optional and defaults to 30000 cells
(define (run str (size 30000))
(let ((tape (array size '(0)))
(i 0)
(result '())
(tim 0)
(prog (compile str)))
(setq tim (time (eval prog)))
(and show-timing (println "Execution time: " tim))
(and quiet (join result))))
; test - run it with (BF:test)
(define (test)
(run "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>."))
; to interpret a string of Brainf*** code, use (BF:run <string>)
; to interpret a Brainf*** code file, use (BF:run (read-file <path-to-file>))
|
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #OxygenBasic | OxygenBasic |
'EVOLUTION
target="METHINKS IT IS LIKE A WEASEL"
le=len target
progeny=string le,"X"
quad seed
declare QueryPerformanceCounter lib "kernel32.dll" (quad*q)
QueryPerformanceCounter seed
Function Rand(sys max) as sys
mov eax,max
inc eax
imul edx,seed,0x8088405
inc edx
mov seed,edx
mul edx
return edx
End Function
sys ls=le-1,cp=0,ct=0,ch=0,fit=0,gens=0
do '1 mutation per generation
i=1+rand ls 'mutation position
ch=64+rand 26 'mutation ascii code
if ch=64 then ch=32 'change '@' to ' '
ct=asc target,i 'target ascii code
cp=asc progeny,i 'parent ascii code
'
if ch=ct then
if cp<>ct then
mid progeny,i,chr ch 'carry improvement
fit++ 'increment fitness
end if
end if
gens++
if fit=le then exit do 'matches target
end do
print progeny " " gens 'RESULT (range 1200-6000 generations)
|
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #NGS | NGS | F fib(n:Int) {
n < 2 returns n
local a = 1, b = 1
# i is automatically local because of for()
for(i=2; i<n; i=i+1) {
local next = a + b
a = b
b = next
}
b
} |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Crystal | Crystal | def factorial(x : Int)
ans = 1
(1..x).each do |i|
ans *= i
end
return ans
end |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #VTL-2 | VTL-2 | 10 N=1
20 #=30
30 #=N/3*0+%=0*110
40 #=N/5*0+%=0*130
50 #=!+30
60 ?=N
70 ?=""
80 N=N+1
90 #=100>N*20
100 #=999
110 ?="Fizz";
120 #=!
130 ?="Buzz";
140 #=!
180 #=70 |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Nim | Nim | import os
var
code = if paramCount() > 0: readFile paramStr 1
else: readAll stdin
tape = newSeq[char]()
d = 0
i = 0
proc run(skip = false): bool =
while d >= 0 and i < code.len:
if d >= tape.len: tape.add '\0'
if code[i] == '[':
inc i
let p = i
while run(tape[d] == '\0'): i = p
elif code[i] == ']':
return tape[d] != '\0'
elif not skip:
case code[i]
of '+': inc tape[d]
of '-': dec tape[d]
of '>': inc d
of '<': dec d
of '.': stdout.write tape[d]
of ',': tape[d] = stdin.readChar
else: discard
inc i
discard run() |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Oz | Oz | declare
Target = "METHINKS IT IS LIKE A WEASEL"
C = 100
MutateRate = 5 %% percent
proc {Main}
X0 = {MakeN {Length Target} RandomChar}
in
for Xi in {Iterate Evolve X0} break:Break do
{System.showInfo Xi}
if Xi == Target then {Break} end
end
end
fun {Evolve Xi}
Copies = {MakeN C fun {$} {Mutate Xi} end}
in
{FoldL Copies MaxByFitness Xi}
end
fun {Mutate Xs}
{Map Xs
fun {$ X}
if {OS.rand} mod 100 < MutateRate then {RandomChar}
else X
end
end}
end
fun {MaxByFitness A B}
if {Fitness B} > {Fitness A} then B else A end
end
fun {Fitness Candidate}
{Length {Filter {List.zip Candidate Target Value.'=='} Id}}
end
Alphabet = & |{List.number &A &Z 1}
fun {RandomChar}
I = {OS.rand} mod {Length Alphabet} + 1
in
{Nth Alphabet I}
end
%% General purpose helpers
fun {Id X} X end
fun {MakeN N F}
Xs = {List.make N}
in
{ForAll Xs F}
Xs
end
fun lazy {Iterate F X}
X|{Iterate F {F X}}
end
in
{Main} |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Nial | Nial | fibi is op n {
if n<2 then
n
else
x1:=0; x2:=1;
for i with tell (n - 1) do
x:=x1+x2;
x1:=x2;
x2:=x;
endfor;
x2
endif}; |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #D | D | uint factorial(in uint n) pure nothrow @nogc
in {
assert(n <= 12);
} body {
uint result = 1;
foreach (immutable i; 1 .. n + 1)
result *= i;
return result;
}
// Computed and printed at compile-time.
pragma(msg, 12.factorial);
void main() {
import std.stdio;
// Computed and printed at run-time.
12.factorial.writeln;
} |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Wart | Wart | for i 1 (i <= 100) ++i
prn (if (divides i 15)
"FizzBuzz"
(divides i 3)
"Fizz"
(divides i 5)
"Buzz"
:else
i) |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Objeck | Objeck | class Brainfu_k {
@program : String; @mem : Int[];
@ip : Int; @dp : Int;
New(program : String, size : Int) {
@program := program;
@mem := Int → New[size];
}
function : Main(args : String[]) ~ Nil {
if(args → Size() = 2) {
Brainfu_k → New(args[0], args[1] → ToInt()) → Execute();
};
}
method : Execute() ~ Nil {
while(@ip < @program → Size()) {
instr := @program → Get(@ip);
select(instr) {
label '>': { @dp += 1; }
label '<': { @dp -= 1; }
label '+': { @mem[@dp] := @mem[@dp] + 1; }
label '-': { @mem[@dp] := @mem[@dp] - 1; }
label '.': { value := @mem[@dp] → As(Char); value → Print(); }
label ',': { @mem[@dp] := Read(); }
label '[': { JumpForward(); }
label ']': { JumpBack(); }
};
@ip += 1;
};
}
method : JumpForward() ~ Nil {
depth := 1;
if(@mem[@dp] = 0) {
while(@ip < @program → Size()) {
instr := @program → Get(@ip);
if(instr = ']') {
depth -= 1; if(depth = 0) { return; };
}
else if(instr = '[') { depth += 1; };
@ip += 1;
};
"*** Unbalanced jump ***" → ErrorLine();
Runtime → Exit(1);
};
}
method : JumpBack() ~ Nil {
depth := 1;
if(@mem[@dp] <> 0) {
while(@ip > 0) {
@ip -= 1;
instr := @program → Get(@ip);
if(instr = '[') {
depth -= 1; if(depth = 0) { return; };
}
else if(instr = ']') { depth += 1; };
};
"*** Unbalanced jump ***" → ErrorLine();
Runtime → Exit(1);
};
}
method : Read() ~ Int {
in := IO.Console → ReadString();
if(in → Size() > 0) { return in → ToInt(); };
return 0;
}
} |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #PARI.2FGP | PARI/GP | target="METHINKS IT IS LIKE A WEASEL";
fitness(s)=-dist(Vec(s),Vec(target));
dist(u,v)=sum(i=1,min(#u,#v),u[i]!=v[i])+abs(#u-#v);
letter()=my(r=random(27)); if(r==26, " ", Strchr(r+65));
insert(v,x=letter())=
{
my(r=random(#v+1));
if(r==0, return(concat([x],v)));
if(r==#v, return(concat(v,[x])));
concat(concat(v[1..r],[x]),v[r+1..#v]);
}
delete(v)=
{
if(#v<2, return([]));
my(r=random(#v)+1);
if(r==1, return(v[2..#v]));
if(r==#v, return(v[1..#v-1]));
concat(v[1..r-1],v[r+1..#v]);
}
mutate(s,rateM,rateI,rateD)=
{
my(v=Vec(s));
if(random(1.)<rateI, v=insert(v));
if(random(1.)<rateD, v=delete(v));
for(i=1,#v,
if(random(1.)<rateM, v[i]=letter())
);
concat(v);
}
evolve(C,rate)=
{
my(parent=concat(vector(#target,i,letter())),ct=0);
while(parent != target,
print(parent" "fitness(parent));
my(v=vector(C,i,mutate(parent,rate,0,0)),best,t);
best=fitness(parent=v[1]);
for(i=2,C,
t=fitness(v[i]);
if(t>best, best=t; parent=v[i])
);
ct++
);
print(parent" "fitness(parent));
ct;
}
evolve(35,.05) |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Nim | Nim | proc Fibonacci(n: int): int64 =
var fn = float64(n)
var p: float64 = (1.0 + sqrt(5.0)) / 2.0
var q: float64 = 1.0 / p
return int64((pow(p, fn) + pow(q, fn)) / sqrt(5.0)) |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Dart | Dart | int fact(int n) {
if(n<0) {
throw new IllegalArgumentException('Argument less than 0');
}
return n==0 ? 1 : n*fact(n-1);
}
main() {
print(fact(10));
print(fact(-1));
} |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #WDTE | WDTE | let io => import 'io';
let s => import 'stream';
let multiple of n => == (% n of) 0;
let fizzbuzz n => switch n {
multiple (* 3 5) => 'FizzBuzz';
multiple 3 => 'Fizz';
multiple 5 => 'Buzz';
default => n;
} -- io.writeln io.stdout;
s.range 1 101 -> s.map fizzbuzz -> s.drain; |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #OCaml | OCaml |
(define (bf program stack-length)
(let ((program (string-append program "]")); end
(program-counter 0)
(stack (make-bytevector stack-length 0))
(stack-pointer 0))
(letrec ((skip (lambda (PC sp in)
(let loop ((pc PC) (sp sp) (in in))
(let ((ch (string-ref program pc))
(pc (+ pc 1)))
(case ch
(#\] (list pc sp in))
(#\[ (apply loop (skip pc sp in)))
(else
(loop pc sp in)))))))
(step (lambda (PC SP IN)
(let loop ((pc PC) (sp SP) (in IN))
(let ((ch (string-ref program pc))
(pc (+ pc 1)))
(case ch
(#\] (list (- PC 1) sp in)) ; the end
(#\[ (if (eq? (ref stack sp) 0)
(apply loop (skip pc sp in))
(apply loop (step pc sp in))))
(#\+ (set-ref! stack sp (mod (+ (ref stack sp) 257) 256))
(loop pc sp in))
(#\- (set-ref! stack sp (mod (+ (ref stack sp) 255) 256))
(loop pc sp in))
(#\> (loop pc (+ sp 1) in))
(#\< (loop pc (- sp 1) in))
(#\. (display (string (ref stack sp)))
(loop pc sp in))
(#\, (let this ((in in))
(cond
((pair? in)
(set-ref! stack sp (car in))
(loop pc sp (cdr in)))
((null? in)
(set-ref! stack sp 0)
(loop pc sp in))
(else
(this (force in))))))
(else ; skip any invalid character
(loop pc sp in))))))))
(step 0 0 (port->bytestream stdin)))))
|
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Pascal | Pascal | PROGRAM EVOLUTION (OUTPUT);
CONST
TARGET = 'METHINKS IT IS LIKE A WEASEL';
COPIES = 100; (* 100 children in each generation. *)
RATE = 1000; (* About one character in 1000 will be a mutation. *)
TYPE
STRLIST = ARRAY [1..COPIES] OF STRING;
FUNCTION RANDCHAR : CHAR;
(* Generate a random letter or space. *)
VAR RANDNUM : INTEGER;
BEGIN
RANDNUM := RANDOM(27);
IF RANDNUM = 26 THEN
RANDCHAR := ' '
ELSE
RANDCHAR := CHR(RANDNUM + ORD('A'))
END;
FUNCTION RANDSTR (SIZE : INTEGER) : STRING;
(* Generate a random string. *)
VAR
N : INTEGER;
S : STRING;
BEGIN
S := '';
FOR N := 1 TO SIZE DO
INSERT(RANDCHAR, S, 1);
RANDSTR := S
END;
FUNCTION FITNESS (CANDIDATE, GOAL : STRING) : INTEGER;
(* Count the number of correct letters in the correct places *)
VAR N, MATCHES : INTEGER;
BEGIN
MATCHES := 0;
FOR N := 1 TO LENGTH(GOAL) DO
IF CANDIDATE[N] = GOAL[N] THEN
MATCHES := MATCHES + 1;
FITNESS := MATCHES
END;
FUNCTION MUTATE (RATE : INTEGER; S : STRING) : STRING;
(* Randomly alter a string. Characters change with probability 1/RATE. *)
VAR
N : INTEGER;
CHANGE : BOOLEAN;
BEGIN
FOR N := 1 TO LENGTH(TARGET) DO
BEGIN
CHANGE := RANDOM(RATE) = 0;
IF CHANGE THEN
S[N] := RANDCHAR
END;
MUTATE := S
END;
PROCEDURE REPRODUCE (RATE : INTEGER; PARENT : STRING; VAR CHILDREN : STRLIST);
(* Generate children with random mutations. *)
VAR N : INTEGER;
BEGIN
FOR N := 1 TO COPIES DO
CHILDREN[N] := MUTATE(RATE, PARENT)
END;
FUNCTION FITTEST(CHILDREN : STRLIST; GOAL : STRING) : STRING;
(* Measure the fitness of each child and return the fittest. *)
(* If multiple children equally match the target, then return the first. *)
VAR
MATCHES, MOST_MATCHES, BEST_INDEX, N : INTEGER;
BEGIN
MOST_MATCHES := 0;
BEST_INDEX := 1;
FOR N := 1 TO COPIES DO
BEGIN
MATCHES := FITNESS(CHILDREN[N], GOAL);
IF MATCHES > MOST_MATCHES THEN
BEGIN
MOST_MATCHES := MATCHES;
BEST_INDEX := N
END
END;
FITTEST := CHILDREN[BEST_INDEX]
END;
VAR
PARENT, BEST_CHILD : STRING;
CHILDREN : STRLIST;
GENERATIONS : INTEGER;
BEGIN
RANDOMIZE;
GENERATIONS := 0;
PARENT := RANDSTR(LENGTH(TARGET));
WHILE NOT (PARENT = TARGET) DO
BEGIN
IF (GENERATIONS MOD 100) = 0 THEN WRITELN(PARENT);
GENERATIONS := GENERATIONS + 1;
REPRODUCE(RATE, PARENT, CHILDREN);
BEST_CHILD := FITTEST(CHILDREN, TARGET);
IF FITNESS(PARENT, TARGET) < FITNESS(BEST_CHILD, TARGET) THEN
PARENT := BEST_CHILD
END;
WRITE('The string was matched in ');
WRITELN(GENERATIONS, ' generations.')
END. |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Nix | Nix | fibonacci = n:
if n <= 1 then n else (fibonacci (n - 1) + fibonacci (n - 2)); |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #dc | dc | [*
* (n) lfx -- (factorial of n)
*]sz
[
1 Sp [product = 1]sz
[ [Loop while 1 < n:]sz
d lp * sp [product = n * product]sz
1 - [n = n - 1]sz
d 1 <f
]Sf d 1 <f
Lfsz [Drop loop.]sz
sz [Drop n.]sz
Lp [Push product.]sz
]sf
[*
* For example, print the factorial of 50.
*]sz
50 lfx psz |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Whitespace | Whitespace | @each &x!console.log x !*&x?{%%x 15 "FizzBuzz" %%x 5 "Buzz" %%x 3 "Fizz" x} @to 100 |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Ol | Ol |
(define (bf program stack-length)
(let ((program (string-append program "]")); end
(program-counter 0)
(stack (make-bytevector stack-length 0))
(stack-pointer 0))
(letrec ((skip (lambda (PC sp in)
(let loop ((pc PC) (sp sp) (in in))
(let ((ch (string-ref program pc))
(pc (+ pc 1)))
(case ch
(#\] (list pc sp in))
(#\[ (apply loop (skip pc sp in)))
(else
(loop pc sp in)))))))
(step (lambda (PC SP IN)
(let loop ((pc PC) (sp SP) (in IN))
(let ((ch (string-ref program pc))
(pc (+ pc 1)))
(case ch
(#\] (list (- PC 1) sp in)) ; the end
(#\[ (if (eq? (ref stack sp) 0)
(apply loop (skip pc sp in))
(apply loop (step pc sp in))))
(#\+ (set-ref! stack sp (mod (+ (ref stack sp) 257) 256))
(loop pc sp in))
(#\- (set-ref! stack sp (mod (+ (ref stack sp) 255) 256))
(loop pc sp in))
(#\> (loop pc (+ sp 1) in))
(#\< (loop pc (- sp 1) in))
(#\. (display (string (ref stack sp)))
(loop pc sp in))
(#\, (let this ((in in))
(cond
((pair? in)
(set-ref! stack sp (car in))
(loop pc sp (cdr in)))
((null? in)
(set-ref! stack sp 0)
(loop pc sp in))
(else
(this (force in))))))
(else ; skip any invalid character
(loop pc sp in))))))))
(step 0 0 (port->bytestream stdin)))))
|
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Perl | Perl | use List::Util 'reduce';
use List::MoreUtils 'false';
### Generally useful declarations
sub randElm
{$_[int rand @_]}
sub minBy (&@)
{my $f = shift;
reduce {$f->($b) < $f->($a) ? $b : $a} @_;}
sub zip
{@_ or return ();
for (my ($n, @a) = 0 ;; ++$n)
{my @row;
foreach (@_)
{$n < @$_ or return @a;
push @row, $_->[$n];}
push @a, \@row;}}
### Task-specific declarations
my $C = 100;
my $mutation_rate = .05;
my @target = split '', 'METHINKS IT IS LIKE A WEASEL';
my @valid_chars = (' ', 'A' .. 'Z');
sub fitness
{false {$_->[0] eq $_->[1]} zip shift, \@target;}
sub mutate
{my $rate = shift;
return [map {rand() < $rate ? randElm @valid_chars : $_} @{shift()}];}
### Main loop
my $parent = [map {randElm @valid_chars} @target];
while (fitness $parent)
{$parent =
minBy \&fitness,
map {mutate $mutation_rate, $parent}
1 .. $C;
print @$parent, "\n";} |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Oberon-2 | Oberon-2 |
MODULE Fibonacci;
IMPORT
Out := NPCT:Console;
PROCEDURE Fibs(VAR r: ARRAY OF LONGREAL);
VAR
i: LONGINT;
BEGIN
r[0] := 1.0; r[1] := 1.0;
FOR i := 2 TO LEN(r) - 1 DO
r[i] := r[i - 2] + r[i - 1];
END
END Fibs;
PROCEDURE FibsR(n: LONGREAL): LONGREAL;
BEGIN
IF n < 2. THEN
RETURN n
ELSE
RETURN FibsR(n - 1) + FibsR(n - 2)
END
END FibsR;
PROCEDURE Show(r: ARRAY OF LONGREAL);
VAR
i: LONGINT;
BEGIN
Out.String("First ");Out.Int(LEN(r),0);Out.String(" Fibonacci numbers");Out.Ln;
FOR i := 0 TO LEN(r) - 1 DO
Out.LongRealFix(r[i],8,0)
END;
Out.Ln
END Show;
PROCEDURE Gen(s: LONGINT);
VAR
x: POINTER TO ARRAY OF LONGREAL;
BEGIN
NEW(x,s);
Fibs(x^);
Show(x^)
END Gen;
PROCEDURE GenR(s: LONGINT);
VAR
i: LONGINT;
BEGIN
Out.String("First ");Out.Int(s,0);Out.String(" Fibonacci numbers (Recursive)");Out.Ln;
FOR i := 1 TO s DO
Out.LongRealFix(FibsR(i),8,0)
END;
Out.Ln
END GenR;
BEGIN
Gen(10);
Gen(20);
GenR(10);
GenR(20);
END Fibonacci.
|
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Delphi | Delphi | program Factorial1;
{$APPTYPE CONSOLE}
function FactorialIterative(aNumber: Integer): Int64;
var
i: Integer;
begin
Result := 1;
for i := 1 to aNumber do
Result := i * Result;
end;
begin
Writeln('5! = ', FactorialIterative(5));
end. |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Wortel | Wortel | @each &x!console.log x !*&x?{%%x 15 "FizzBuzz" %%x 5 "Buzz" %%x 3 "Fizz" x} @to 100 |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #PARI.2FGP | PARI/GP | BF(prog)={
prog=Vec(Str(prog));
my(codeptr,ptr=1,v=vector(1000),t);
while(codeptr++ <= #prog,
t=prog[codeptr];
if(t=="+",
v[ptr]++
,
if(t=="-",
v[ptr]--
,
if(t==">",
ptr++
,
if(t=="<",
ptr--
,
if(t=="[" && !v[ptr],
t=1;
while(t,
if(prog[codeptr++]=="[",t++);
if(prog[codeptr]=="]",t--)
);
);
if(t=="]"&&v[ptr],
t=1;
while(t,
if(prog[codeptr--]=="[",t--);
if(prog[codeptr]=="]",t++)
)
);
if(t==".",
print1(Strchr(v[ptr]))
);
if(t==",",
v[ptr]=Vecsmall(input)[1]
)
)
)
)
)
)
}; |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Phix | Phix | with javascript_semantics
constant target = "METHINKS IT IS LIKE A WEASEL",
AZS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ",
C = 5000, -- children in each generation
P = 15 -- probability of mutation (1 in 15)
function fitness(string sample, string target)
return sum(sq_eq(sample,target))
end function
function mutate(string s, integer n)
for i=1 to length(s) do
if rand(n)=1 then
s[i] = AZS[rand(length(AZS))]
end if
end for
return s
end function
string parent = mutate(target,1) -- (mutate with 100% probability)
sequence samples = repeat(0,C)
integer gen = 0, best, fit, best_fit = fitness(parent,target)
while parent!=target do
printf(1,"Generation%3d: %s, fitness %3.2f%%\n", {gen, parent, (best_fit/length(target))*100})
best_fit = -1
for i=1 to C do
samples[i] = mutate(parent, P)
fit = fitness(samples[i], target)
if fit > best_fit then
best_fit = fit
best = i
end if
end for
parent = samples[best]
gen += 1
end while
printf(1,"Finally, \"%s\"\n",{parent})
|
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Objeck | Objeck | bundle Default {
class Fib {
function : Main(args : String[]), Nil {
for(i := 0; i <= 10; i += 1;) {
Fib(i)->PrintLine();
};
}
function : native : Fib(n : Int), Int {
if(n < 2) {
return n;
};
return Fib(n-1) + Fib(n-2);
}
}
} |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Draco | Draco | /* Note that ulong is 32 bits, so fac(12) is the largest
* supported value. This is why the input parameter
* is a byte. The parameters are all unsigned. */
proc nonrec fac(byte n) ulong:
byte i;
ulong rslt;
rslt := 1;
for i from 2 upto n do
rslt := rslt * i
od;
rslt
corp
proc nonrec main() void:
byte i;
for i from 0 upto 12 do
writeln(i:2, "! = ", fac(i):9)
od
corp |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Wren | Wren | for (i in 1..100) {
if (i % 15 == 0) {
System.print("FizzBuzz")
} else if (i % 3 == 0) {
System.print("Fizz")
} else if (i % 5 == 0) {
System.print("Buzz")
} else {
System.print(i)
}
} |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Pascal | Pascal |
program rcExceuteBrainF;
uses
Crt;
Const
DataSize= 1024; // Size of Data segment
MaxNest= 1000; // Maximum nesting depth of []
procedure ExecuteBF(Source: string);
var
Dp: pByte; // Used as the Data Pointer
DataSeg: Pointer; // Start of the DataSegment (Cell 0)
Ip: pChar; // Used as instruction Pointer
LastIp: Pointer; // Last adr of code.
JmpStack: array[0..MaxNest-1] of pChar; // Stack to Keep track of active "[" locations
JmpPnt: Integer; // Stack pointer ^^
JmpCnt: Word; // Used to count brackets when skipping forward.
begin
// Set up then data segment
getmem(DataSeg,dataSize);
dp:=DataSeg;
fillbyte(dp^,dataSize,0);
// Set up the JmpStack
JmpPnt:=-1;
// Set up Instruction Pointer
Ip:=@Source[1];
LastIp:=@Source[length(source)];
if Ip=nil then exit;
// Main Execution loop
repeat { until Ip > LastIp }
Case Ip^ of
'<': dec(dp);
'>': inc(dp);
'+': inc(dp^);
'-': dec(dp^);
'.': write(stdout,chr(dp^));
',': dp^:=ord(readkey);
'[': if dp^=0 then
begin
// skip forward until matching bracket;
JmpCnt:=1;
while (JmpCnt>0) and (ip<=lastip) do
begin
inc(ip);
Case ip^ of
'[': inc(JmpCnt);
']': dec(JmpCnt);
#0: begin
Writeln(StdErr,'Error brackets don''t match');
halt;
end;
end;
end;
end else begin
// Add location to Jump stack
inc(JmpPnt);
JmpStack[jmpPnt]:=ip;
end;
']': if dp^>0 then
// Jump Back to matching [
ip:=JmpStack[jmpPnt]
else
// Remove Jump from stack
dec(jmpPnt);
end;
inc(ip);
until Ip>lastIp;
freemem(DataSeg,dataSize);
end;
Const
HelloWorldWiki = '++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>'+
'---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.';
pressESCtoCont = '>[-]+++++++[<++++++++++>-]<->>[-]+++++++[<+++++++++++'+
'+>-]<->>[-]++++[<++++++++>-]+>[-]++++++++++[<++++++++'+
'++>-]>[-]++++++++[<++++++++++++++>-]<.++.+<.>..<<.<<.'+
'-->.<.>>.>>+.-----.<<.[<<+>>-]<<.>>>>.-.++++++.<++++.'+
'+++++.>+.<<<<++.>+[>+<--]>++++...';
waitForEsc = '[-]>[-]++++[<+++++++>-]<->[-]>+[[-]<<[>+>+<<-]'+'>>[<'+
'<+>>-],<[->-<]>]';
begin
// Execute "Hello World" example from Wikipedia
ExecuteBF(HelloWorldWiki);
// Print text "press ESC to continue....." and wait for ESC to be pressed
ExecuteBF(pressESCtoCont+waitForEsc);
end.
|
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #PHP | PHP |
define('TARGET','METHINKS IT IS LIKE A WEASEL');
define('TBL','ABCDEFGHIJKLMNOPQRSTUVWXYZ ');
define('MUTATE',15);
define('COPIES',30);
define('TARGET_COUNT',strlen(TARGET));
define('TBL_COUNT',strlen(TBL));
// Determine number of different chars between a and b
function unfitness($a,$b)
{
$sum=0;
for($i=0;$i<strlen($a);$i++)
if($a[$i]!=$b[$i]) $sum++;
return($sum);
}
function mutate($a)
{
$tbl=TBL;
for($i=0;$i<strlen($a);$i++) $out[$i]=mt_rand(0,MUTATE)?$a[$i]:$tbl[mt_rand(0,TBL_COUNT-1)];
return(implode('',$out));
}
$tbl=TBL;
for($i=0;$i<TARGET_COUNT;$i++) $tspec[$i]=$tbl[mt_rand(0,TBL_COUNT-1)];
$parent[0]=implode('',$tspec);
$best=TARGET_COUNT+1;
$iters=0;
do {
for($i=1;$i<COPIES;$i++) $parent[$i]=mutate($parent[0]);
for($best_i=$i=0; $i<COPIES;$i++) {
$unfit=unfitness(TARGET,$parent[$i]);
if($unfit < $best || !$i) {
$best=$unfit;
$best_i=$i;
}
}
if($best_i>0) $parent[0]=$parent[$best_i];
$iters++;
print("Generation $iters, score $best: $parent[0]\n");
} while($best);
|
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Objective-C | Objective-C | -(long)fibonacci:(int)position
{
long result = 0;
if (position < 2) {
result = position;
} else {
result = [self fibonacci:(position -1)] + [self fibonacci:(position -2)];
}
return result;
} |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Dragon | Dragon | select "std"
factorial = 1
n = readln()
for(i=1,i<=n,++i)
{
factorial = factorial * i
}
showln "factorial of " + n + " is " + factorial
|
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #X86_Assembly | X86 Assembly |
; x86_64 linux nasm
section .bss
number resb 4
section .data
fizz: db "Fizz"
buzz: db "Buzz"
newLine: db 10
section .text
global _start
_start:
mov rax, 1 ; initialize counter
loop:
push rax
call fizzBuzz
pop rax
inc rax
cmp rax, 100
jle loop
mov rax, 60
mov rdi, 0
syscall
fizzBuzz:
mov r10, rax
mov r15, 0 ; boolean fizz or buzz
checkFizz:
xor rdx, rdx ; clear rdx for division
mov rbx, 3
div rbx
cmp rdx, 0 ; modulo result here
jne checkBuzz
mov r15, 1
mov rsi, fizz
mov rdx, 4
mov rax, 1
mov rdi, 1
syscall
checkBuzz:
mov rax, r10
xor rdx, rdx
mov rbx, 5
div rbx
cmp rdx, 0
jne finishLine
mov r15, 1
mov rsi, buzz
mov rdx, 4
mov rax, 1
mov rdi, 1
syscall
finishLine: ; print number if no fizz or buzz
cmp r15, 1
je nextLine
mov rax, r10
call printNum
ret
nextLine:
mov rsi, newLine
mov rdx, 1
mov rax, 1
mov rdi, 1
syscall
ret
printNum: ; write proper digits into number buffer
cmp rax, 100
jl lessThanHundred
mov byte [number], 49
mov byte [number + 1], 48
mov byte [number + 2], 48
mov rdx, 3
jmp print
lessThanHundred: ; get digits to write through division
xor rdx, rdx
mov rbx, 10
div rbx
add rdx, 48
cmp rax, 0
je lessThanTen
add rax, 48
mov byte [number], al
mov byte [number + 1], dl
mov rdx, 2
jmp print
lessThanTen:
mov byte [number], dl
mov rdx, 1
print:
mov byte [number + rdx], 10 ; add newline
inc rdx
mov rax, 1
mov rdi, 1
mov rsi, number
syscall
ret
|
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Perl | Perl | #!/usr/bin/perl
my %code = split ' ', <<'END';
> $ptr++
< $ptr--
+ $memory[$ptr]++
- $memory[$ptr]--
, $memory[$ptr]=ord(getc)
. print(chr($memory[$ptr]))
[ while($memory[$ptr]){
] }
END
my ($ptr, @memory) = 0;
eval join ';', map @code{ /./g }, <>; |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Picat | Picat | go =>
_ = random2(),
Target = "METHINKS IT IS LIKE A WEASEL",
Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ",
C = 50, % Population size in each generation
M = 80, % Mutation rate per individual in a generation (0.8)
evo(Target,Chars,C,M),
nl.
evo(Target,Chars,C,M) =>
if member(T,Target), not member(T, Chars) then
printf("The character %w is not in the character set: %w\n", T, Chars);
halt
end,
% first random string
TargetLen = Target.length,
Parent = random_chars(Chars,TargetLen),
%
% Until current fitness reaches a score of perfect match
% with the target string keep generating new populations
%
CurrentFitness = 0,
Gen = 1,
while (CurrentFitness < TargetLen)
println([gen=Gen, currentFitness=CurrentFitness, parent=Parent]),
Gen := Gen + 1,
[Parent2,CurrentFitness2] = generation(C,Chars,Target,M,Parent),
CurrentFitness := CurrentFitness2,
Parent := Parent2
end,
println([gen=Gen, currentFitness=CurrentFitness, parent=Parent]),
printf("\nFound a perfect fitness (%d) at generation %d\n", CurrentFitness, Gen),
nl.
%
% Generate a random string
%
random_chars(Chars, N) = [Chars[my_rand(Len)] : _ in 1..N] =>
Len = Chars.length.
%
% Increment the fitness for every position in the string
% S that matches the target
%
fitness(S,Target) = sum([1: I in 1..Target.length, S[I] == Target[I]]).
%
% If a random number between 1 and 100 is inside the
% bounds of mutation randomly alter a character in the string
%
mutate(S,M,Chars) = S2 =>
S2 = copy_term(S),
if my_rand(100) <= M then
S2[my_rand(S.length)] := Chars[my_rand(Chars.length)]
end.
% Get a random value between 1 and N
my_rand(N) = 1+(random() mod N).
%
% Create the next population of parent
%
generation(C,Chars,Target,M,Parent) = [NextParent,NextFitness] =>
% generate a random population
Population = [mutate(Parent,M,Chars) : _ in 1..C],
% Find the member of the population with highest fitness,
NextParent = Parent,
NextFitness = fitness(Parent,Target),
foreach(X in Population)
XF = fitness(X,Target),
if XF > NextFitness then
NextParent := X,
NextFitness := XF
end
end. |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #OCaml | OCaml | let fib_iter n =
if n < 2 then
n
else let fib_prev = ref 1
and fib = ref 1 in
for num = 2 to n - 1 do
let temp = !fib in
fib := !fib + !fib_prev;
fib_prev := temp
done;
!fib |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #DWScript | DWScript | function IterativeFactorial(n : Integer) : Integer;
var
i : Integer;
begin
Result := 1;
for i := 2 to n do
Result *= i;
end; |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #XLISP | XLISP | (defun fizzbuzz ()
(defun fizzb (x y)
(display (cond
((= (mod x 3) (mod x 5) 0) "FizzBuzz")
((= (mod x 3) 0) "Fizz")
((= (mod x 5) 0) "Buzz")
(t x)))
(newline)
(if (< x y)
(fizzb (+ x 1) y)))
(fizzb 1 100))
(fizzbuzz) |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Phix | Phix | procedure bfi(string pgm)
sequence jumptable = repeat(0,length(pgm)),
loopstack = {},
data = repeat(0,10) -- size??
integer skip = 0, ch, loopstart, pc, dp
--
-- compile (pack/strip comments and link jumps)
--
for i=1 to length(pgm) do
ch = pgm[i]
switch ch do
case '[': loopstack = append(loopstack,i-skip);
pgm[i-skip] = ch;
case ']': loopstart = loopstack[$];
loopstack = loopstack[1..-2];
jumptable[i-skip] = loopstart;
jumptable[loopstart] = i-skip;
fallthrough
case '+','-','<','>',',','.': pgm[i-skip] = ch;
default: skip += 1
end switch
end for
if length(loopstack) then ?9/0 end if
pgm = pgm[1..-1-skip]
--
-- main execution loop
--
pc = 1
dp = 1
while pc<=length(pgm) do
ch = pgm[pc]
switch ch do
case '>': dp += 1 if dp>length(data) then dp = 1 end if
case '<': dp -= 1 if dp<1 then dp = length(data) end if
case '+': data[dp] += 1
case '-': data[dp] -= 1
case ',': data[dp] = iff(platform()=JS?'?':getc(0))
case '.': puts(1,data[dp])
case '[': if data[dp]=0 then pc = jumptable[pc] end if
case ']': if data[dp]!=0 then pc = jumptable[pc] end if
default: ?9/0
end switch
pc += 1
end while
end procedure
constant bf="++++++++[>++++[>++>++++>+++>+<<<<-]>++>->+>>+[<]<-]>>.>>.+.<.>>.<<<++.>---------.>------.<----.++++++++.>>+.>++.+++."
constant fb="++++++++[>++++[>++>++++>+++>+<<<<-]>++>->+>>+[<]<-]>>.>>.+.<.>>.<<<+++.>---.>------.++++++++.<--.>>+.>++.+++.,"
bfi(bf)
bfi(fb)
|
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #PicoLisp | PicoLisp | (load "@lib/simul.l")
(setq *Target (chop "METHINKS IT IS LIKE A WEASEL"))
# Generate random character
(de randChar ()
(if (=0 (rand 0 26))
" "
(char (rand `(char "A") `(char "Z"))) ) )
# Fitness function (Hamming distance)
(de fitness (A)
(cnt = A *Target) )
# Genetic algorithm
(gen
(make # Parent population
(do 100 # C = 100 children
(link
(make
(do (length *Target)
(link (randChar)) ) ) ) ) )
'((A) # Termination condition
(prinl (maxi fitness A)) # Print the fittest element
(member *Target A) ) # and check if solution is found
'((A B) # Recombination function
(mapcar
'((C D) (if (rand T) C D)) # Pick one of the chars
A B ) )
'((A) # Mutation function
(mapcar
'((C)
(if (=0 (rand 0 10)) # With a proability of 10%
(randChar) # generate a new char, otherwise
C ) ) # return the current char
A ) )
fitness ) # Selection function |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Octave | Octave | % recursive
function fibo = recfibo(n)
if ( n < 2 )
fibo = n;
else
fibo = recfibo(n-1) + recfibo(n-2);
endif
endfunction |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Dyalect | Dyalect | func factorial(n) {
if n < 2 {
1
} else {
n * factorial(n - 1)
}
} |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #XMIDAS | XMIDAS | startmacro
loop 100 count
calc/quiet three ^count 3 modulo
calc/quiet five ^count 5 modulo
if ^three eq 0 and ^five eq 0
say "fizzbuzz"
elseif ^three eq 0
say "fizz"
elseif ^five eq 0
say "buzz"
else
say ^count
endif
endloop
endmacro |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #PHP | PHP | <?php
function brainfuck_interpret(&$s, &$_s, &$d, &$_d, &$i, &$_i, &$o) {
do {
switch($s[$_s]) {
case '+': $d[$_d] = chr(ord($d[$_d]) + 1); break;
case '-': $d[$_d] = chr(ord($d[$_d]) - 1); break;
case '>': $_d++; if(!isset($d[$_d])) $d[$_d] = chr(0); break;
case '<': $_d--; break;
case '.': $o .= $d[$_d]; break;
case ',': $d[$_d] = $_i==strlen($i) ? chr(0) : $i[$_i++]; break;
case '[':
if((int)ord($d[$_d]) == 0) {
$brackets = 1;
while($brackets && $_s++ < strlen($s)) {
if($s[$_s] == '[')
$brackets++;
else if($s[$_s] == ']')
$brackets--;
}
}
else {
$pos = $_s++-1;
if(brainfuck_interpret($s, $_s, $d, $_d, $i, $_i, $o))
$_s = $pos;
}
break;
case ']': return ((int)ord($d[$_d]) != 0);
}
} while(++$_s < strlen($s));
}
function brainfuck($source, $input='') {
$data = array();
$data[0] = chr(0);
$data_index = 0;
$source_index = 0;
$input_index = 0;
$output = '';
brainfuck_interpret($source, $source_index,
$data, $data_index,
$input, $input_index,
$output);
return $output;
}
$code = "
>++++++++[<+++++++++>-]<.>>+>+>++>[-]+<[>[->+<<++++>]<<]>.+++++++..+++.>
>+++++++.<<<[[-]<[-]>]<+++++++++++++++.>>.+++.------.--------.>>+.>++++.
";
$inp = '123';
print brainfuck( $code, $inp );
|
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Pike | Pike | string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ";
string mutate(string data, int rate)
{
array(int) alphabet=(array(int))chars;
multiset index = (multiset)enumerate(sizeof(data));
while(rate)
{
int pos = random(index);
data[pos]=random(alphabet);
rate--;
}
return data;
}
int fitness(string input, string target)
{
return `+(@`==(((array)input)[*], ((array)target)[*]));
}
void main()
{
array(string) alphabet = chars/"";
string target = "METHINKS IT IS LIKE A WEASEL";
string parent = "";
while(sizeof(parent) != sizeof(target))
{
parent += random(alphabet);
}
int count;
write(" %5d: %s\n", count, parent);
while (parent != target)
{
string child = mutate(parent, 2);
count++;
if (fitness(child, target) > fitness(parent, target))
{
write(" %5d: %s\n", count, child);
parent = child;
}
}
} |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Oforth | Oforth | : fib 0 1 rot #[ tuck + ] times drop ; |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #Dylan | Dylan |
define method factorial (n)
if (n < 1)
error("invalid argument");
else
reduce1(\*, range(from: 1, to: n))
end
end method;
|
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Xojo | Xojo | For i As Integer = 1 To 100
If i Mod 3 = 0 And i Mod 5 = 0 Then
Print("FizzBuzz")
ElseIf i Mod 3 = 0 Then
Print("Fizz")
ElseIf i Mod 5 = 0 Then
Print("Buzz")
Else
Print(Str(i))
End If
Next |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #PicoLisp | PicoLisp | (off "Program")
(de compile (File)
(let Stack NIL
(setq "Program"
(make
(in File
(while (char)
(case @
(">"
(link
'(setq Data
(or
(cddr Data)
(con (cdr Data) (cons 0 (cons Data))) ) ) ) )
("<"
(link
'(setq Data
(or
(cadr Data)
(set (cdr Data) (cons 0 (cons NIL Data))) ) ) ) )
("+" (link '(inc Data)))
("-" (link '(dec Data)))
("." (link '(prin (char (car Data)))))
("," (link '(set Data (char (read)))))
("["
(link
'(setq Code
((if (=0 (car Data)) cdar cdr) Code) ) )
(push 'Stack (chain (cons))) )
("]"
(unless Stack
(quit "Unbalanced ']'") )
(link
'(setq Code
((if (n0 (car Data)) cdar cdr) Code) ) )
(let (There (pop 'Stack) Here (cons There))
(chain (set There Here)) ) ) ) ) ) ) )
(when Stack
(quit "Unbalanced '['") ) ) )
(de execute ()
(let Data (cons 0 (cons)) # Create initial cell
(for (Code "Program" Code) # Run program
(eval (pop 'Code)) )
(while (cadr Data) # Find beginning of data
(setq Data @) )
(filter prog Data '(T NIL .)) ) ) # Return data space |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Pony | Pony | use "random"
actor Main
let _env: Env
let _rand: MT = MT // Mersenne Twister
let _target: String = "METHINKS IT IS LIKE A WEASEL"
let _possibilities: String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ "
let _c: U16 = 100 // number of spawn per generation
let _min_mutate_rate: F64 = 0.09
let _perfect_fitness: USize = _target.size()
var _parent: String = ""
new create(env: Env) =>
_env = env
_parent = mutate(_target, 1.0)
var iter: U64 = 0
while not _target.eq(_parent) do
let rate: F64 = new_mutate_rate()
iter = iter + 1
if (iter % 100) == 0 then
_env.out.write(iter.string() + ": " + _parent)
_env.out.write(", fitness: " + fitness(_parent).string())
_env.out.print(", rate: " + rate.string())
end
var best_spawn = ""
var best_fit: USize = 0
var i: U16 = 0
while i < _c do
let spawn = mutate(_parent, rate)
let spawn_fitness = fitness(spawn)
if spawn_fitness > best_fit then
best_spawn = spawn
best_fit = spawn_fitness
end
i = i + 1
end
if best_fit > fitness(_parent) then
_parent = best_spawn
end
end
_env.out.print(_parent + ", " + iter.string())
fun fitness(trial: String): USize =>
var ret_val: USize = 0
var i: USize = 0
while i < trial.size() do
try
if trial(i)? == _target(i)? then
ret_val = ret_val + 1
end
end
i = i + 1
end
ret_val
fun new_mutate_rate(): F64 =>
let perfect_fit = _perfect_fitness.f64()
((perfect_fit - fitness(_parent).f64()) / perfect_fit) * (1.0 - _min_mutate_rate)
fun ref mutate(parent: String box, rate: F64): String =>
var ret_val = recover trn String end
for char in parent.values() do
let rnd_real: F64 = _rand.real()
if rnd_real <= rate then
let rnd_int: U64 = _rand.int(_possibilities.size().u64())
try
ret_val.push(_possibilities(rnd_int.usize())?)
end
else
ret_val.push(char)
end
end
consume ret_val |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Ol | Ol | FIBON:
REM Fibonacci sequence is generated to the Organiser II floating point variable limit.
REM CLEAR/ON key quits.
REM Mikesan - http://forum.psion2.org/
LOCAL A,B,C
A=1 :B=1 :C=1
PRINT A,
DO
C=A+B
A=B
B=C
PRINT A,
UNTIL GET=1 |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #D.C3.A9j.C3.A0_Vu | Déjà Vu | factorial:
1
while over:
* over
swap -- swap
drop swap |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #XPath_2.0 | XPath 2.0 | for $n in 1 to 100 return
concat('fizz'[not($n mod 3)], 'buzz'[not($n mod 5)], $n[$n mod 15 = (1,2,4,7,8,11,13,14)]) |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #PL.2FM | PL/M | 100H:
/* CP/M BDOS CALLS */
BDOS: PROCEDURE (FN, ARG) BYTE;
DECLARE FN BYTE, ARG ADDRESS;
GO TO 5;
END BDOS;
READ$CHAR: PROCEDURE BYTE; RETURN BDOS(1, 0); END READ$CHAR;
WRITE$CHAR: PROCEDURE (CHAR); DECLARE CHAR BYTE;
CHAR = BDOS(2, CHAR); END WRITE$CHAR;
PRINT: PROCEDURE (STRING); DECLARE STRING ADDRESS;
STRING = BDOS(9, STRING); END PRINT;
OPEN$FILE: PROCEDURE (FCB) BYTE; DECLARE FCB ADDRESS;
RETURN BDOS(15, FCB); END OPEN$FILE;
READ$FILE: PROCEDURE (FCB, ADDR) BYTE;
DECLARE (FCB, ADDR) ADDRESS, FOO BYTE;
FOO = BDOS(26, ADDR);
RETURN BDOS(20, FCB);
END READ$FILE;
EXIT: PROCEDURE; MEMORY(0) = BDOS(0,0); END EXIT;
/* TOP OF AVAILABLE MEMORY IN CP/M */
DECLARE MTPTR ADDRESS INITIAL (6), MEM$TOP BASED MTPTR ADDRESS;
/* FILE GIVEN ON COMMAND LINE */
DECLARE FCB1 LITERALLY '5CH';
/* PRINT ERROR AND EXIT */
ERROR: PROCEDURE (STRING);
DECLARE STRING ADDRESS;
CALL PRINT(STRING);
CALL EXIT;
END ERROR;
/* OPEN FILE */
IF OPEN$FILE(FCB1) = 0FFH THEN
CALL ERROR(.'CANNOT OPEN INPUT FILE$');
/* READ FILE BLOCK BY BLOCK */
DECLARE MP ADDRESS, M BASED MP BYTE;
MEMORY(0) = 26;
MP = .MEMORY + 1;
DO WHILE READ$FILE(FCB1, MP) <> 1;
MP = MP + 128;
END;
M = 26; /* TERMINATE WITH EOF */
MP = MP + 1;
/* CLEAR THE REST OF MEMORY */
DECLARE X ADDRESS;
DO X = 0 TO MEM$TOP-MP-1;
M(X) = 0;
END;
/* BRAINF*** I/O WITH CR/LF TRANSLATION */
BF$WRITE: PROCEDURE (CHAR);
DECLARE CHAR BYTE;
IF CHAR = 10 THEN CALL WRITE$CHAR(13);
CALL WRITE$CHAR(CHAR);
END BF$WRITE;
BF$READ: PROCEDURE BYTE;
DECLARE EOF$REACHED BYTE INITIAL (0), CH BYTE;
IF EOF$REACHED THEN RETURN 0;
CH = READ$CHAR;
IF CH = 13 THEN RETURN 10;
ELSE IF CH = 26 THEN DO;
EOF$REACHED = 1;
RETURN 0;
END;
ELSE RETURN CH;
END BF$READ;
/* EXECUTE COMMANDS */
DECLARE IP ADDRESS, I BASED IP BYTE;
DECLARE EOF$REACHED BYTE INITIAL (0), DEPTH ADDRESS;
DECLARE BRACKET$ERR DATA ('MISMATCHED BRACKETS$');
DECLARE B$OPEN LITERALLY '91', B$CLOSE LITERALLY '93';
IP = .MEMORY + 1;
DO WHILE I <> 26;
IF I = '+' THEN M = M + 1;
ELSE IF I = '-' THEN M = M - 1;
ELSE IF I = '>' THEN MP = MP + 1;
ELSE IF I = '<' THEN MP = MP - 1;
ELSE IF I = '.' THEN CALL BF$WRITE(M);
ELSE IF I = ',' THEN M = BF$READ;
ELSE IF I = B$OPEN AND M = 0 THEN DO;
DEPTH = 1;
DO WHILE DEPTH > 0;
IP = IP + 1;
IF I = B$OPEN THEN DEPTH = DEPTH + 1;
ELSE IF I = B$CLOSE THEN DEPTH = DEPTH - 1;
ELSE IF I = 26 THEN CALL ERROR(.BRACKET$ERR);
END;
END;
ELSE IF I = B$CLOSE AND M <> 0 THEN DO;
DEPTH = 1;
DO WHILE DEPTH > 0;
IP = IP - 1;
IF I = B$OPEN THEN DEPTH = DEPTH - 1;
ELSE IF I = B$CLOSE THEN DEPTH = DEPTH + 1;
ELSE IF I = 26 THEN CALL ERROR(.BRACKET$ERR);
END;
END;
IP = IP + 1;
END;
CALL EXIT;
EOF |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Prolog | Prolog | target("METHINKS IT IS LIKE A WEASEL").
rndAlpha(64, 32). % Generate a single random character
rndAlpha(P, P). % 32 is a space, and 65->90 are upper case
rndAlpha(Ch) :- random(N), P is truncate(64+(N*27)), !, rndAlpha(P, Ch).
rndTxt(0, []). % Generate some random text (fixed length)
rndTxt(Len, [H|T]) :- succ(L, Len), rndAlpha(H), !, rndTxt(L, T).
score([], [], Score, Score). % Score a generated mutation (count diffs)
score([Ht|Tt], [Ht|Tp], C, Score) :- !, score(Tt, Tp, C, Score).
score([_|Tt], [_|Tp], C, Score) :- succ(C, N), !, score(Tt, Tp, N, Score).
score(Txt, Score, Target) :- !, score(Target, Txt, 0, Score).
mutate(_, [], []). % mutate(Probability, Input, Output)
mutate(P, [H|Txt], [H|Mut]) :- random(R), R < P, !, mutate(P, Txt, Mut).
mutate(P, [_|Txt], [M|Mut]) :- rndAlpha(M), !, mutate(P, Txt, Mut).
weasel(Tries, _, _, mutation(0, Result)) :- % No differences=success
format('~w~4|:~w~3| - ~s\n', [Tries, 0, Result]).
weasel(Tries, Chance, Target, mutation(S, Value)) :- % output progress
format('~w~4|:~w~3| - ~s\n', [Tries, S, Value]), !, % and call again
weasel(Tries, Chance, Target, Value).
weasel(Tries, Chance, Target, Start) :-
findall(mutation(S,M), % Generate 30 mutations, select the best.
(between(1, 30, _), mutate(Chance, Start, M), score(M,S,Target)),
Mutations), % List of 30 mutations and their scores
sort(Mutations, [Best|_]), succ(Tries, N),
!, weasel(N, Chance, Target, Best).
weasel :- % Chance->probability for a mutation, T=Target, Start=initial text
target(T), length(T, Len), rndTxt(Len, Start), Chance is 1 - (1/(Len+1)),
!, weasel(0, Chance, T, Start). |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #OPL | OPL | FIBON:
REM Fibonacci sequence is generated to the Organiser II floating point variable limit.
REM CLEAR/ON key quits.
REM Mikesan - http://forum.psion2.org/
LOCAL A,B,C
A=1 :B=1 :C=1
PRINT A,
DO
C=A+B
A=B
B=C
PRINT A,
UNTIL GET=1 |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #E | E | pragma.enable("accumulator")
def factorial(n) {
return accum 1 for i in 2..n { _ * i }
} |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #XPL0 | XPL0 | code CrLf=9, IntOut=11, Text=12;
int N;
[for N:= 1 to 100 do
[if rem(N/3)=0 then Text(0,"Fizz");
if rem(N/5)=0 then Text(0,"Buzz")
else if rem(N/3)#0 then IntOut(0,N);
CrLf(0);
];
] |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Pointless | Pointless | -- Code based on
-- https://github.com/allisio/pointless/blob/master/lib/examples/brainfuck.ptls
output =
iterate(run, vm)
|> takeUntil(isFinished)
|> map(vm => vm.outVal)
|> filter(notEq(None))
|> map(char)
|> printElems
----------------------------------------------------------
vm = VM {
ip = 0
dp = 0
data = zeroArray(1000)
inVals = map(ord, readLines)
outVal = None
}
----------------------------------------------------------
-- "hello.bf" contains brainf*** hello world code
ops = toArray(readFile("hello.bf"))
----------------------------------------------------------
run(vm) = vm |> clearOutput |> eval |> advance
advance(vm) = vm with $.ip += 1
isFinished(vm) = vm.ip >= length(ops)
clearOutput(vm) = vm with $.outVal = None
----------------------------------------------------------
jumps = getJumps(0, [], {})
getJumps(i, stack, jumps) = cond {
case (i == length(ops)) jumps
case (ops[i] == "[")
getJumps(i + 1, [i] ++ stack, jumps)
case (ops[i] == "]")
getJumps(i + 1, tail(stack), jumps with {
$[i] = head(stack)
$[head(stack)] = i
})
else getJumps(i + 1, stack, jumps)
}
----------------------------------------------------------
eval(vm) = cond {
case (op == ">") vm with $.dp += 1
case (op == "<") vm with $.dp -= 1
case (op == "+") vm with $.data[vm.dp] += 1
case (op == "-") vm with $.data[vm.dp] -= 1
case (op == ".") vm with $.outVal = byte
case (op == ",") vm with {
$.data[vm.dp] = head(vm.inVals)
$.inVals = tail(vm.inVals)
}
case (op == "[")
if byte != 0 then vm
else (vm with $.ip = jumps[vm.ip])
case (op == "]")
if byte == 0 then vm
else (vm with $.ip = jumps[vm.ip])
else vm
} where {
op = ops[vm.ip]
byte = vm.data[vm.dp]
} |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #PureBasic | PureBasic | Define population = 100, mutationRate = 6
Define.s target$ = "METHINKS IT IS LIKE A WEASEL"
Define.s charSet$ = "ABCDEFGHIJKLMNOPQRSTUVWXYZ "
Procedure.i fitness(Array aspirant.c(1), Array target.c(1))
Protected i, len, fit
len = ArraySize(aspirant())
For i = 0 To len
If aspirant(i) = target(i): fit +1: EndIf
Next
ProcedureReturn fit
EndProcedure
Procedure mutatae(Array parent.c(1), Array child.c(1), Array charSetA.c(1), rate.i)
Protected i, L, maxC
L = ArraySize(child())
maxC = ArraySize(charSetA())
For i = 0 To L
If Random(100) < rate
child(i) = charSetA(Random(maxC))
Else
child(i) = parent(i)
EndIf
Next
EndProcedure
Procedure.s cArray2string(Array A.c(1))
Protected S.s, len
len = ArraySize(A())+1 : S = Space(len)
CopyMemory(@A(0), @S, len * SizeOf(Character))
ProcedureReturn S
EndProcedure
Define mutationRate, maxChar, target_len, i, maxfit, gen, fit, bestfit
Dim targetA.c(Len(target$) - 1)
CopyMemory(@target$, @targetA(0), StringByteLength(target$))
Dim charSetA.c(Len(charSet$) - 1)
CopyMemory(@charSet$, @charSetA(0), StringByteLength(charSet$))
maxChar = Len(charSet$) - 1
maxfit = Len(target$)
target_len = Len(target$) - 1
Dim parent.c(target_len)
Dim child.c(target_len)
Dim Bestchild.c(target_len)
For i = 0 To target_len
parent(i) = charSetA(Random(maxChar))
Next
fit = fitness (parent(), targetA())
OpenConsole()
PrintN(Str(gen) + ": " + cArray2string(parent()) + ": Fitness= " + Str(fit) + "/" + Str(maxfit))
While bestfit <> maxfit
gen + 1
For i = 1 To population
mutatae(parent(),child(),charSetA(), mutationRate)
fit = fitness (child(), targetA())
If fit > bestfit
bestfit = fit: CopyArray(child(), Bestchild())
EndIf
Next
CopyArray(Bestchild(), parent())
PrintN(Str(gen) + ": " + cArray2string(parent()) + ": Fitness= " + Str(bestfit) + "/" + Str(maxfit))
Wend
PrintN("Press any key to exit"): Repeat: Until Inkey() <> "" |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Order | Order | #include <order/interpreter.h>
#define ORDER_PP_DEF_8fib_rec \
ORDER_PP_FN(8fn(8N, \
8if(8less(8N, 2), \
8N, \
8add(8fib_rec(8sub(8N, 1)), \
8fib_rec(8sub(8N, 2))))))
ORDER_PP(8fib_rec(10)) |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #EasyLang | EasyLang | func factorial n . r .
r = 1
i = 2
while i <= n
r = r * i
i += 1
.
.
call factorial 7 r
print r |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #XSLT | XSLT | <?xml version="1.0" encoding="utf-8" ?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output method="text" encoding="utf-8"/>
<!-- Outputs a line for a single FizzBuzz iteration. -->
<xsl:template name="fizzbuzz-single">
<xsl:param name="n"/>
<!-- $s will be "", "Fizz", "Buzz", or "FizzBuzz". -->
<xsl:variable name="s">
<xsl:if test="$n mod 3 = 0">Fizz</xsl:if>
<xsl:if test="$n mod 5 = 0">Buzz</xsl:if>
</xsl:variable>
<!-- Output $s. If $s is blank, also output $n. -->
<xsl:value-of select="$s"/>
<xsl:if test="$s = ''">
<xsl:value-of select="$n"/>
</xsl:if>
<!-- End line. -->
<xsl:value-of select="' '"/>
</xsl:template>
<!-- Calls fizzbuzz-single over each value in a range. -->
<xsl:template name="fizzbuzz-range">
<!-- Default parameters: From 1 through 100 -->
<xsl:param name="startAt" select="1"/>
<xsl:param name="endAt" select="$startAt + 99"/>
<!-- Simulate a loop with tail recursion. -->
<!-- Loop condition -->
<xsl:if test="$startAt <= $endAt">
<!-- Loop body -->
<xsl:call-template name="fizzbuzz-single">
<xsl:with-param name="n" select="$startAt"/>
</xsl:call-template>
<!-- Increment counter, repeat -->
<xsl:call-template name="fizzbuzz-range">
<xsl:with-param name="startAt" select="$startAt + 1"/>
<xsl:with-param name="endAt" select="$endAt"/>
</xsl:call-template>
</xsl:if>
</xsl:template>
<!-- Main procedure -->
<xsl:template match="/">
<!-- Default parameters are used -->
<xsl:call-template name="fizzbuzz-range"/>
</xsl:template>
</xsl:stylesheet> |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Potion | Potion | # Where `code` is a string.
bf = (code) :
tape = (0)
tape_pos = 0
brackets = ()
i = -1
while (++i < code length) :
if (code(i) == ">"): if (++tape_pos == tape length): tape append(0)..
elsif (code(i) == "<"): tape_pos--.
elsif (code(i) == "+"): tape(tape_pos) = tape(tape_pos) + 1.
elsif (code(i) == "-"): tape(tape_pos) = tape(tape_pos) - 1.
elsif (code(i) == "."): tape(tape_pos) chr print.
elsif (code(i) == ","): tape(tape_pos) = read at(0) ord.
elsif (code(i) == "["): brackets push(i).
elsif (code(i) == "]") :
if (tape(tape_pos) == 0): brackets pop.
else: i = brackets(-1).
.
.
. |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #Python | Python | from string import letters
from random import choice, random
target = list("METHINKS IT IS LIKE A WEASEL")
charset = letters + ' '
parent = [choice(charset) for _ in range(len(target))]
minmutaterate = .09
C = range(100)
perfectfitness = float(len(target))
def fitness(trial):
'Sum of matching chars by position'
return sum(t==h for t,h in zip(trial, target))
def mutaterate():
'Less mutation the closer the fit of the parent'
return 1-((perfectfitness - fitness(parent)) / perfectfitness * (1 - minmutaterate))
def mutate(parent, rate):
return [(ch if random() <= rate else choice(charset)) for ch in parent]
def que():
'(from the favourite saying of Manuel in Fawlty Towers)'
print ("#%-4i, fitness: %4.1f%%, '%s'" %
(iterations, fitness(parent)*100./perfectfitness, ''.join(parent)))
def mate(a, b):
place = 0
if choice(xrange(10)) < 7:
place = choice(xrange(len(target)))
else:
return a, b
return a, b, a[:place] + b[place:], b[:place] + a[place:]
iterations = 0
center = len(C)/2
while parent != target:
rate = mutaterate()
iterations += 1
if iterations % 100 == 0: que()
copies = [ mutate(parent, rate) for _ in C ] + [parent]
parent1 = max(copies[:center], key=fitness)
parent2 = max(copies[center:], key=fitness)
parent = max(mate(parent1, parent2), key=fitness)
que() |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #Oz | Oz | fun{FibI N}
Temp = {NewCell 0}
A = {NewCell 0}
B = {NewCell 1}
in
for I in 1..N do
Temp := @A + @B
A := @B
B := @Temp
end
@A
end |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #EchoLisp | EchoLisp |
(define (fact n)
(for/product ((f (in-range 2 (1+ n)))) f))
(fact 10)
→ 3628800
|
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Yabasic | Yabasic | for(i = 1; i <= 100; i++) {
if(i % 3 == 0)
write, format="%s", "Fizz";
if(i % 5 == 0)
write, format="%s", "Buzz";
if(i % 3 && i % 5)
write, format="%d", i;
write, "";
} |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #Prolog | Prolog | /******************************************
Starting point, call with program in atom.
*******************************************/
brain(Program) :-
atom_chars(Program, Instructions),
process_bf_chars(Instructions).
brain_from_file(File) :- % or from file...
read_file_to_codes(File, Codes, []),
maplist(char_code, Instructions, Codes),
process_bf_chars(Instructions).
process_bf_chars(Instructions) :-
phrase(bf_to_pl(Code), Instructions, []),
Code = [C|_],
instruction(C, Code, mem([], [0])), !.
/********************************************
DCG to parse the bf program into prolog form
*********************************************/
bf_to_pl([]) --> [].
bf_to_pl([loop(Ins)|Next]) --> loop_start, bf_to_pl(Ins), loop_end, bf_to_pl(Next).
bf_to_pl([Ins|Next]) --> bf_code(Ins), bf_to_pl(Next).
bf_to_pl(Ins) --> [X], { \+ member(X, ['[',']',>,<,+,-,'.',',']) }, bf_to_pl(Ins). % skip non bf characters
loop_start --> ['['].
loop_end --> [']'].
bf_code(next_addr) --> ['>'].
bf_code(prev_addr) --> ['<'].
bf_code(inc_caddr) --> ['+'].
bf_code(dec_caddr) --> ['-'].
bf_code(out_caddr) --> ['.'].
bf_code(in_caddr) --> [','].
/**********************
Instruction Processor
***********************/
instruction([], _, _).
instruction(I, Code, Mem) :-
mem_instruction(I, Mem, UpdatedMem),
next_instruction(Code, NextI, NextCode),
!, % cuts are to force tail recursion, so big programs will run
instruction(NextI, NextCode, UpdatedMem).
% to loop, add the loop code to the start of the program then execute
% when the loop has finished it will reach itself again then can retest for zero
instruction(loop(LoopCode), Code, Mem) :-
caddr(Mem, X),
dif(X, 0),
append(LoopCode, Code, [NextI|NextLoopCode]),
!,
instruction(NextI, [NextI|NextLoopCode], Mem).
instruction(loop(_), Code, Mem) :-
caddr(Mem, 0),
next_instruction(Code, NextI, NextCode),
!,
instruction(NextI, NextCode, Mem).
% memory is stored in two parts:
% 1. a list with the current address and everything after it
% 2. a list with the previous memory in reverse order
mem_instruction(next_addr, mem(Mb, [Caddr]), mem([Caddr|Mb], [0])).
mem_instruction(next_addr, mem(Mb, [Caddr,NextAddr|Rest]), mem([Caddr|Mb], [NextAddr|Rest])).
mem_instruction(prev_addr, mem([PrevAddr|RestOfPrev], Caddrs), mem(RestOfPrev, [PrevAddr|Caddrs])).
% wrap instructions at the byte boundaries as this is what most programmers expect to happen
mem_instruction(inc_caddr, MemIn, MemOut) :- caddr(MemIn, 255), update_caddr(MemIn, 0, MemOut).
mem_instruction(inc_caddr, MemIn, MemOut) :- caddr(MemIn, Val), succ(Val, IncVal), update_caddr(MemIn, IncVal, MemOut).
mem_instruction(dec_caddr, MemIn, MemOut) :- caddr(MemIn, 0), update_caddr(MemIn, 255, MemOut).
mem_instruction(dec_caddr, MemIn, MemOut) :- caddr(MemIn, Val), succ(DecVal, Val), update_caddr(MemIn, DecVal, MemOut).
% input and output
mem_instruction(out_caddr, Mem, Mem) :- caddr(Mem, Val), char_code(Char, Val), write(Char).
mem_instruction(in_caddr, MemIn, MemOut) :-
get_single_char(Code),
char_code(Char, Code),
write(Char),
map_input_code(Code,MappedCode),
update_caddr(MemIn, MappedCode, MemOut).
% need to map the newline if it is not a proper newline character (system dependent).
map_input_code(13,10) :- nl.
map_input_code(C,C).
% The value at the current address
caddr(mem(_, [Caddr]), Caddr).
caddr(mem(_, [Caddr,_|_]), Caddr).
% The updated value at the current address
update_caddr(mem(BackMem, [_]), Caddr, mem(BackMem, [Caddr])).
update_caddr(mem(BackMem, [_,M|Mem]), Caddr, mem(BackMem, [Caddr,M|Mem])).
% The next instruction, and remaining code
next_instruction([_], [], []).
next_instruction([_,NextI|Rest], NextI, [NextI|Rest]). |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.
A mutate function that given a string and a mutation rate returns a copy of the string, with some characters probably mutated.
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Assess the fitness of the parent and all the copies to the target and make the most fit string the new parent, discarding the others.
repeat until the parent converges, (hopefully), to the target.
See also
Wikipedia entry: Weasel algorithm.
Wikipedia entry: Evolutionary algorithm.
Note: to aid comparison, try and ensure the variables and functions mentioned in the task description appear in solutions
A cursory examination of a few of the solutions reveals that the instructions have not been followed rigorously in some solutions. Specifically,
While the parent is not yet the target:
copy the parent C times, each time allowing some random probability that another character might be substituted using mutate.
Note that some of the the solutions given retain characters in the mutated string that are correct in the target string. However, the instruction above does not state to retain any of the characters while performing the mutation. Although some may believe to do so is implied from the use of "converges"
(:* repeat until the parent converges, (hopefully), to the target.
Strictly speaking, the new parent should be selected from the new pool of mutations, and then the new parent used to generate the next set of mutations with parent characters getting retained only by not being mutated. It then becomes possible that the new set of mutations has no member that is fitter than the parent!
As illustration of this error, the code for 8th has the following remark.
Create a new string based on the TOS, changing randomly any characters which
don't already match the target:
NOTE: this has been changed, the 8th version is completely random now
Clearly, this algo will be applying the mutation function only to the parent characters that don't match to the target characters!
To ensure that the new parent is never less fit than the prior parent, both the parent and all of the latest mutations are subjected to the fitness test to select the next parent.
| #R | R | set.seed(1234, kind="Mersenne-Twister")
## Easier if the string is a character vector
target <- unlist(strsplit("METHINKS IT IS LIKE A WEASEL", ""))
charset <- c(LETTERS, " ")
parent <- sample(charset, length(target), replace=TRUE)
mutaterate <- 0.01
## Number of offspring in each generation
C <- 100
## Hamming distance between strings normalized by string length is used
## as the fitness function.
fitness <- function(parent, target) {
sum(parent == target) / length(target)
}
mutate <- function(parent, rate, charset) {
p <- runif(length(parent))
nMutants <- sum(p < rate)
if (nMutants) {
parent[ p < rate ] <- sample(charset, nMutants, replace=TRUE)
}
parent
}
evolve <- function(parent, mutate, fitness, C, mutaterate, charset) {
children <- replicate(C, mutate(parent, mutaterate, charset),
simplify=FALSE)
children <- c(list(parent), children)
children[[which.max(sapply(children, fitness, target=target))]]
}
.printGen <- function(parent, target, gen) {
cat(format(i, width=3),
formatC(fitness(parent, target), digits=2, format="f"),
paste(parent, collapse=""), "\n")
}
i <- 0
.printGen(parent, target, i)
while ( ! all(parent == target)) {
i <- i + 1
parent <- evolve(parent, mutate, fitness, C, mutaterate, charset)
if (i %% 20 == 0) {
.printGen(parent, target, i)
}
}
.printGen(parent, target, i) |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow and are mostly used as an exercise in recursion).
The sequence is sometimes extended into negative numbers by using a straightforward inverse of the positive definition:
Fn = Fn+2 - Fn+1, if n<0
support for negative n in the solution is optional.
Related tasks
Fibonacci n-step number sequences
Leonardo numbers
References
Wikipedia, Fibonacci number
Wikipedia, Lucas number
MathWorld, Fibonacci Number
Some identities for r-Fibonacci numbers
OEIS Fibonacci numbers
OEIS Lucas numbers
| #PARI.2FGP | PARI/GP | fibonocci(n) |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterative or recursive.
Support for trapping negative n errors is optional.
Related task
Primorial numbers
| #EGL | EGL |
function fact(n int in) returns (bigint)
if (n < 0)
writestdout("No negative numbers");
return (0);
end
ans bigint = 1;
for (i int from 1 to n)
ans *= i;
end
return (ans);
end
|
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
| #Yorick | Yorick | for(i = 1; i <= 100; i++) {
if(i % 3 == 0)
write, format="%s", "Fizz";
if(i % 5 == 0)
write, format="%s", "Buzz";
if(i % 3 && i % 5)
write, format="%d", i;
write, "";
} |
http://rosettacode.org/wiki/Execute_Brain**** | Execute Brain**** | Execute Brain**** is an implementation of Brainf***.
Other implementations of Brainf***.
RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages.
Below are links to each of the versions of RCBF.
An implementation need only properly implement the following instructions:
Command
Description
>
Move the pointer to the right
<
Move the pointer to the left
+
Increment the memory cell under the pointer
-
Decrement the memory cell under the pointer
.
Output the character signified by the cell at the pointer
,
Input a character and store it in the cell at the pointer
[
Jump past the matching ] if the cell under the pointer is 0
]
Jump back to the matching [ if the cell under the pointer is nonzero
Any cell size is allowed, EOF (End-O-File) support is optional, as is whether you have bounded or unbounded memory.
| #PureBasic | PureBasic | [ stack ] is switch.arg ( --> [ )
[ switch.arg put ] is switch ( x --> )
[ switch.arg release ] is otherwise ( --> )
[ switch.arg share != iff ]else[ done
otherwise ]'[ do ]done[ ] is case ( x --> )
[ dip tuck unrot poke swap ] is poketape ( [ n n --> [ n )
[ 1+ over size over = if [ dip [ 0 join ] ] ] is stepright ( [ n --> [ n )
[ dup 0 = iff [ 0 rot join swap ] else [ 1 - ] ] is stepleft ( [ n --> [ n )
[ 2dup peek 1 + poketape ] is increment ( [ n --> [ n )
[ 2dup peek 1 - poketape ] is decrement ( [ n --> [ n )
[ 2dup peek emit ] is print ( [ n --> [ n )
[ temp take dup $ "" = iff 0 else behead
swap temp put poketape ] is getchar ( [ n --> [ n )
[ 2dup peek 0 = ] is zero ( [ n --> [ n b )
[ temp put $ "" swap witheach
[ switch
[ char > case [ $ "stepright " join ]
char < case [ $ "stepleft " join ]
char + case [ $ "increment " join ]
char - case [ $ "decrement " join ]
char . case [ $ "print " join ]
char , case [ $ "getchar " join ]
char [ case [ $ "[ zero if done " join ]
char ] case [ $ "zero until ] " join ]
otherwise ( ignore ) ] ]
0 nested 0 rot quackery temp release 2drop ] is brainf*** ( $ $ --> ) |
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