#include <stdio.h>
#define ARRAY_LENGTH 3

int add(int a, int b){
    return a + b;
}

int mult(int a, int b){
    return a * b;
}

int mod(int a, int b){
    return a % b;
}

int main(){
    int (*op)(int, int) = add;
    int x = 6, y = 5;
    printf("%d\n", op(x, y));
    op = mult;
    printf("%d\n", op(x, y));
    op = mod;
    printf("%d\n", op(x, y));
}