Copies and references

1#include <iostream>
2using namespace std;
3 
4void addOne(int x) {
5    x = x + 1;
6}
7 
8void addOneRef(int &x) {
9    x = x + 1;
10}
11 
12int main() {
13    int n = 5;
14    addOne(n);
15    cout << n << endl;
16    addOneRef(n);
17    cout << n << endl;
18    return 0;
19}