Intro to recursive functions in C

main.c

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
// 4 => 4 + 3 + 2 + 1 = 10
// 4 => 4 + 2 + 0 = 6
// 156 => 1 + 5 + 6 = 12
int f(int x) {
    if (x == 0) {
        return 0;
    }
    printf("Hello from f with x = %d\n", x);
    return x + f(x - 1);
}

// return 4 + 3 + 2 + 1 + 0

int main(int argc, char* argv[]) {
    int result = f(4);
    printf("The result of calling f is %d\n", result);
    return 0;
}