// Fig. 3.20: fig03_20.cpp
// Comparing call-by-value and call-by-reference
// with references.
#include <iostream.h>

int squareByValue( int );
void squareByReference( int & );
                                                   
int main()
{
   int x = 2, z = 4;

   cout << "x = " << x << " before squareByValue\n"
        << "Value returned by squareByValue: "
        << squareByValue( x ) << endl
        << "x = " << x << " after squareByValue\n" << endl;

   cout << "z = " << z << " before squareByReference" << endl;
   squareByReference( z );
   cout << "z = " << z << " after squareByReference" << endl;

   return 0;
}

int squareByValue( int a )
{
   return a *= a;   // caller's argument not modified
}

void squareByReference( int &cRef )
{
   cRef *= cRef;    // caller's argument modified
}