Explanation of functions needed.

The following is stated in the book I am reading at the moment.

Code:

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int factorial(int x)
{
  int i;
  for(i=1; i < x; i++)
    x *= i;
  return x;
}

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Code:

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int a=5, b;
b = factorial(a);

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Gives variable b the value 120 at the end. Could someone explain to me how this is calculated?

It doesn't. The code is wrong.

Quote:

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Originally Posted by King Mir

It doesn't. The code is wrong.

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Am I right when I say the result is 25 or what exactly is wrong. Ow, yeah, maybe handy to say but it is pseudo code if I am right.

It's trying to modify x, which is an input. Pretty sure while that input x is local to main(), the x referenced inside of factorial() is a different variable (but of the same name), local to factorial().

The way it's supposed to work though is you get an input, say 7, and multiply 7 by every integer between 1 and 7...that code would take the x (7) and multiply it by 1, store it to x...take x, multiply by 2, store, take x, multiply by 3, store, up until 6 (7 < 7 breaks the loop), effectively giving you 7 * 6 * 5 * 4 * 3 * 2 * 1.

Quote:

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Originally Posted by Epy

It's trying to modify x, which is an input. Pretty sure while that input x is local to main(), the x referenced inside of factorial() is a different variable (but of the same name), local to factorial().

The way it's supposed to work though is you get an input, say 7, and multiply 7 by every integer between 1 and 7...that code would take the x (7) and multiply it by 1, store it to x...take x, multiply by 2, store, take x, multiply by 3, store, up until 6 (7 < 7 breaks the loop), effectively giving you 7 * 6 * 5 * 4 * 3 * 2 * 1.

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I'm an idiot. Now I see it.

Thanks for the help the both of you.