#include <iostream>
#include <cstdlib>
using namespace std;

// The variables in swap() are passed by reference.  Changes are
// actually made to the arguments.  If the main function is run
// with swappy() instead, the actual arguments are not changed.
// Notice that the actual function call in main() looks just
// like every old function call.  

void swap( float &x, float &y );
void swappy( float x, float y );

int main()
{
    float p = -3.14, q = 2.72;
    cout << "p = " << p << " and q = " << q << endl;
    cout << "And now the swap..." << endl;
    swap( p, q );
    cout << "p = " << p << " and q = " << q << endl;
        
    cout << "\n\n"; system( "PAUSE" );
    return( EXIT_SUCCESS );
}

void swap( float &x,  float &y )
{
    float temp = x;
    x = y;
    y = temp;
}

void swappy( float x, float y )
{
    float temp = x;
    x = y;
    y = temp;
}