Facorial Calculator

[Arrexel]

As stated in my previous post, I have been bored lately, writing occasionally useful code. This time I have written a very simple collection of lines that calculates the factorial of a number. This code is useful for calculating the total number of possibilities that a word list generator can produce.

Code: Select all

a = long(raw_input("Number: "))
b = a
factorial = a

while a > 1:
        a -= 1
        factorial = factorial * a
       
print "The factorial of",b,"is:",factorial



Factorial:
Mathematics. the product of a given positive integer multiplied by all lesser positive integers: The quantity four factorial (4!) = 4 · 3 · 2 · 1 = 24.
Symbol: n!, where n is the given integer.

-Reference.com

[mutants_r_us_guild]

I was bored and read this post.. decided to do the same thing in JS.

Code: Select all

<script>
   factorial=1;
   num=prompt("Type number:", "");
   for(a=num;a>1;a--){
   factorial = factorial * a;
   }
   document.write("<h1><br><center>" + num + "!=" + factorial);
</script>


[GuGaBoY]

nice coding
by the way, factorials are usually high numbers that won't fit on normal int variables.
This library helped me to deal with huge numbers in C/C++:
http://www.nongnu.org/hpalib/
it's well documented

[Arrexel]

Ah, that makes sense. I'll update the code to fix this problem when I get a chance later tonight. And nice work, mutants

EDIT:
Well, that was simple enough.

[mischief]

C++ and GMP

Code: Select all

mpz_class factorial(mpz_class num)
{
   mpz_class tot(num--);
   while(num != 0)
   {
      tot *= num--;
   }
   return tot;
}

[mutants_r_us_guild]

Here's my script turned into a function Enjoy:

Code: Select all

function factorial(num)
{
   fact=1;
   for(a=num;a>1;a--){
   fact = fact * a;
   }
   return fact
}


[Arrexel]

Lol, a lot of different scripts being posted
Nice work.

[novalyphe]

Very simple perl version.

Code: Select all

#!/usr/bin/perl

print "Enter an integer number: \n";

$Number = <STDIN>;

for ($n = ($Number-1) ; $n >1; $n -=1) {
$Number *= $n; }

print "The factorial of that number is: $Number\n";


[acskurucz]

Code: Select all

<?php
$factorial="1";
$n=1000;
for($i=1; $i<=$n; ++$i) $factorial=bcmul($factorial, $i);

echo $factorial;
?>

It can handle very very very big numbers.

[mutants_r_us_guild]

Code: Select all

<?php
$factorial="1";
$n=1000;
for($i=1; $i<=$n; ++$i) $factorial=bcmul($factorial, $i);

echo $factorial;
?>

It can handle very very very big numbers.

I turned your code into a function:

function factorial($x){
$factorial="1";
for($i=1; $i<=$x; ++$i) $factorial=bcmul($factorial, $i);
return $factorial;
}


P.S. I incorporated that function into my bot