/* n! using while. */
#include <stdio.h>

int main() {
    int	i, n, f;

    printf("Enter n: ");
    scanf("%d", &n);

    f = 1;  /* 0! */
    i = 1;
    while (i <= n) {
	f *= i; /* Now, f = i! */
	++i;
    }
    printf("%d! = %d\n", n, f);
    return 0;
}