C++ Factorial Program Using Recursion

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 4 is 24.

4! = 4 * 3 * 2 *1
4! = 24

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

The following program demonstrates a recursive program to find the factorial of a number −

Example

 Live Demo

#include <iostream>
using namespace std;
int fact(int n) {
   if ((n==0)||(n==1))
   return 1;
   else
   return n*fact(n-1);
}
int main() {
   int n = 4;
   cout<<"Factorial of "<<n<<" is "<<fact(n);
   return 0;
}

Output

Factorial of 4 is 24

In the above program, the function fact() is a recursive function. The main() function calls fact() using the number whose factorial is required. This is demonstrated by the following code snippet.

cout<<"Factorial of "<<n<<" is "<<fact(n);

If the number is 0 or 1, then fact() returns 1. If the number is any other, then fact() recursively calls itself with the value n-1.

This is demonstrated using the following code snippet.

int fact(int n) {
   if ((n==0)||(n==1))
   return 1;
   else
   return n*fact(n-1);
}