#include <iostream>
using namespace std;
// The function modifies variables in the calling environment by
// receiving parameters of type reference, and then modifying
// the variables that are referred to.
void set(int &a, int &b, int &c) {
a = 1;
b = 2;
c = 3;
}
int main() {
int a = 0;
int b = 0;
int c = 0;
// print initial values
cout << a << ' ' << b << ' ' << c << endl;
// modify the local a, b, c by passing references to them.
set(a, b, c);
// print values of a, b, c
cout << a << ' ' << b << ' ' << c << endl;
return 0;
}