#include <iostream>
using namespace std;
// instead of "pass-by-value," let's change
//   this to "pass-by-reference"
// by adding the "&" to each variable, the
//   variables a and b refer back to x and y
void swap( int & a, int & b )
{
    // swap values of a and b:
    int temp = a;
    a = b;
    b = temp;
    cout << "a is " << a << " and b is " << b << endl;

    // no need for return at the end!
    return;  // <== this is an OPTIONAL exit-point
}

// the swap() function has "void" as its return type,
//   which means that no value is returned
// functions return either 0 or 1 result
// if we want to "return" 2 or more values, use
//   the pass-by-reference mechanism

int main()
{
    int x = 5, y = 12;
    swap( x, y );
    cout << "x is " << x << " and y is " << y << endl;


    return 0;
}