C++ Program to Find Factorial of a Number using Iteration

Factorial of a non-negative integer n is the product of all the positive integers that are less than or equal to n.

For example: The factorial of 6 is 720.

6! = 6 * 5 * 4 * 3 * 2 *1
6! = 720

The factorial of an integer can be found using a recursive program or an iterative program.

A for loop can be used to find the factorial of a number using an iterative program. This is demonstrated as follows.

Example

 Live Demo

#include <iostream>
using namespace std;
int main() {
   int n = 6, fact = 1, i;
   for(i=1; i<=n; i++)
   fact = fact * i;
   cout<<"Factorial of "<< n <<" is "<<fact;
   return 0;
}

Output

Factorial of 6 is 720

In the above program, the for loop runs from 1 to n. For each iteration of the loop, fact is multiplied with i. The final value of fact is the product of all numbers from 1 to n. This is demonstrated using the following code snippet.

for(i=1; i<=n; i++)
fact = fact * i;