Scope (local vs global) functions in C++

 #include <iostream>

using namespace std;

int num = 25;

void sum(int a, int b) {

    cout << num << endl;

    int s = a + b;

    cout << s << endl;

}

int main(){

    sum(5, 4);

    int s = 10;

    cout << num << endl;

    return 0;

}