#include <stdio.h>

int main() {
	int i = factorial(10);
	int j = factorial(15);
	int k = factorial(20);
	
	printf("factorial(10) = %12d\n", i);
	printf("factorial(15) = %12d\n", j);
	printf("factorial(20) = %12d\n", k);
	 
	return 0;	
}


/* Figure 5.7  Function to Compute Factorial */
/*
* Computes n!
* Pre: n is greater than or equal to zero
*/

int
factorial(int n)
{
      int i,         /* local variables */
          product;   /* accumulator for product computation */

      product = 1;
      /* Computes the product n x (n-1) x (n-2) x ... x 2 x 1 */
      for (i = n;  i > 1;  --i) {
           product = product * i;
      }

      /* Returns function result */
      return (product);
}