Factorial of a Number in C

This program calculates the factorial of a given positive integer.

#include <stdio.h>

 int main() {

    int n, i;

    unsigned long long factorial = 1;

    printf("Enter a positive integer: ");

    scanf("%d", &n);

    for(i = 1; i <= n; ++i) {

        factorial *= i;

    }

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

    return 0;

}