// Ch. 13 Demo Program #5
// Mr. Minich
// Purpose - to demonstrate the use of const with reference parameters. 

// YOU MUST DELETE THE CONST KEYWORDS IN ORDER TO SUCCESSFULLY COMPILE & 
//    EXECUTE THIS PROGRAM

#include <iostream.h>

void display1(int &);        // used to demonstrate danger of not protecting
			     //   reference parameters with use of const
void display2( const int &); // used to demonstrate the caution of using const 
			     //   reference parameters

int main()
{
	int value = 5;			// used to demonstrate use of const reference 
					//    parameters

	cout << "Initially, value is:\t" << value << endl;

	display1(value);

	cout << "After display1 is called, value is:\t" << value << endl;

	display2(value);

	cout << "After display2 is called, value is:\t" << value << endl << endl;

	return 0;

}// end of main

void display1(int & incoming)
{
	incoming = 7;
}// end of display1

void display2( const int & incoming)
// const is to be used in front of a parameter if you do not intend to modify the 
//   value of its corresponding argument in the calling function. This example is 
//   trivial since we are purposefully changing the value of incoming (i.e. value)
//   in order to demonstrate how the use of const will result in a compiler error
{
	incoming = 8;      // compiler error message: l-value specifies const object
}// end of display1