Iterative or Recursive Factorial

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Hi
I've implemented factorial recursively this way:

C++

int factorial(int x){
	if (x <= 0)
		return 1;
	else
		return (x*factorial(x - 1));
}

int _tmain(int argc, _TCHAR* argv[])
{
	std::cout << "Please enter your number :::";
	int x;
	std::cin >> x;
	std::cout<<"factorial(" << x << ") = "<< factorial(x);
	getchar(); getchar();
}

which way of implementing such code is more useful writing it using iteration and loops or writing it recursively such as above?

Posted 28-Jan-15 0:52am

m.r.m.40

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3 solutions

Solution 2

You are correct, in this case recursion is best and cleanest.

Posted 28-Jan-15 1:02am

Richard MacCutchan

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Snesh Prajapati · Accepted Answer · 2015-01-28T00:59:00

Solution 1

It is better to use Iterations/loops in this case.
For details explanation please visit:
http://www.informit.com/articles/article.aspx?p=1874865[^]

Thanks.

Posted 28-Jan-15 0:59am

Snesh Prajapati

nv3 · Accepted Answer · 2015-01-28T02:38:00

It depends on what you understand by "best". Is it fastest, easiest code to comprehend, most elegant, easiest to maintain, etc.?

If you had to implement it as a library function the speed would obviously play a big role. And that would certainly have you implement it in a loop. A recursive implementation is much slower, because each multiplication does also consume the time of a procedure call. So most people will say that the iterative implementation is the "best". If you were to give a programming class and wanted to demonstrate the concept of recursive functions your goal could be different, though.