Factorial Algorithm

ALGORITHM F(n)

//Computes n! recursively

//Input: A nonnegative integer n

//Output: The value of n!

if n = 0 return 1

else return F (n - 1) ∗ n

C program:

#include <stdio.h>

 int factorial(int c){

     if(c==1){

        return 1;

     }

     else{

 return c*factorial(c-1);

 }

 }

int main()

{

  int c, n, fact = 1;

  printf("Enter a number to calculate its factorial\n");

  scanf("%d", &n);

  fact=factorial(n);

 // for (c = 1; c <= n; c++)

    //fact = fact * c;

  printf("Factorial of %d = %d\n", n, fact);

  return 0;

}

Output:

Enter a number to calculate its factorial

5

Factorial of 5 = 120