C++ Functions

#include <iostream>
#include <cmath> // import library

int main() {
    // sqrt() is from cmath
    std::cout << sqrt(9);
}

void fun(string a, string b) {
    std::cout << a + " " + b;
}
void fun(string a) {
    std::cout << a;
}
void fun(int a) {
    std::cout << a;
}

#include <iostream>
int add(int a, int b) {
    return a + b;  
}
int main() {
    std::cout << add(10, 20); 
}

add is a function taking 2 ints and returning int