what type is this c++

#include <iostream>

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

int main() {
    int num1 = 5;
    int num2 = 7;
    int result = add(num1, num2);

    std::cout << "Sum of " << num1 << " and " << num2 << " is: " << result << std::endl;

    return 0;
}