Power of recursion

factorial.c

#include <stdio.h>

unsigned int factorial(unsigned int x);

int main() {
    /* testing code */
    printf("1! = %i\n", factorial(1));
    printf("3! = %i\n", factorial(3));
    printf("5! = %i\n", factorial(5));
}

unsigned int factorial(unsigned int x) {
    return (x > 1) ? x * factorial(x - 1) : 1;
}