#include <iostream.h>

void main()
{
	int Boys = 3, Girls = 5;
	void PassByValue(int males, int females);
	void Reference(int &m, int &f);
	void Pointers(int *u, int *v);
	
	cout << "At startup, within main()";
	cout << "\n\tBoys  = " << Boys;
	cout << "\n\tGirls = " << Girls;

	cout << "\nPassing arguments by value = Copy";
	PassByValue(Boys, Girls);
	cout << "\nAfter calling PassByValue(), within main()";
	cout << "\n\tBoys  = " << Boys;
	cout << "\n\tGirls = " << Girls;

	cout << "\nPassing arguments by reference";
	Reference(Boys, Girls);
	cout << "\nAfter calling Reference(), within main()";
	cout << "\n\tBoys  = " << Boys;
	cout << "\n\tGirls = " << Girls;

	cout << "\nPassing arguments pointers";
	Pointers(&Boys, &Girls);
	cout << "\nAfter calling Pointers(), within main()";
	cout << "\n\tBoys  = " << Boys;
	cout << "\n\tGirls = " << Girls;
	cout << "\n";
}

void PassByValue(int b, int g)
{
	b += 3, g += 4;

	cout << "\nWithin PassByValue(), now";
	cout << "\n\tBoys  = " << b;
	cout << "\n\tGirls = " << g;
}

void Reference(int &b, int &g)
{
	b = b + 8, g = g + 5;

	cout << "\nWithin Reference(), now";
	cout << "\n\tBoys  = " << b;
	cout << "\n\tGirls = " << g;
}

void Pointers(int *b, int *g)
{
	*b = 44, *g = 52;

	cout << "\nWithin Pointers(), now";
	cout << "\n\tBoys  = " << *b;
	cout << "\n\tGirls = " << *g;
}

This would produce:
 

At startup, within main() Boys = 3 Girls = 5 Passing arguments by value = Copy Within PassByValue(), now Boys = 6 Girls = 9 After calling PassByValue(), within main() Boys = 3 Girls = 5 Passing arguments by reference Within Reference(), now Boys = 11 Girls = 10 After calling Reference(), within main() Boys = 11 Girls = 10 Passing arguments pointers Within Pointers(), now Boys = 44 Girls = 52 After calling Pointers(), within main() Boys = 44 Girls = 52

 

C++ Tutorial	Copyright © 2001 FunctionX, Inc.