#include <iostream>
using namespace std;

    void dontEdit(int a) {
       a = 2;
    }

    void edit(int &a) {
       a = 2;
    }

    int main() {
        int a = 5;
        cout << "a is: " << a << endl;
        dontEdit(a);
        cout << "a is: " << a << endl;
        edit(a);
        cout << "a is: " << a << endl;
        return 0;
    }