// Zig Herzog
// Oct. 23, 2007
// Example of passing multiple values back and forth using
// the method "pass-by-reference"

// Note that the first two paramters are passed by reference , the third
// one by value. In function main() the variable "control" is merely
// printed to show that passing-by-value is NOT a two-way street.

#include <iostream>

using namespace std ;

void ex2 ( int& , int& , int ) ;    //  <<<<  prototyping
void flip ( int& , int& ) ;

int main () 
{
 
	int v1 , v2 , control ; 

	cout << "Give two integer values to be ordered : " ;
	cin >> v1 >> v2 ;
	cout << "Return in which order, 0=increasing 1=decreasing : " ;
	cin >> control ; 
	ex2 ( v1 , v2 , control ) ;   // <<<<< call to function ex1()

	cout << "v1=" << v1 << " v2=" << v2 << " control=" << control << endl ;
}

//////////////  Definition of function ex2() ////////////////////////

void ex2 ( int& v , int& w , int cc )
{

	int tmp ;      // local variable
	if ( cc == 0 )
	{  // Increasing order
	   if ( v > w )
	   {  
              flip ( v , w ) ;	// flip values
	   }
	}
	else
	{  // decreasing order
	   if ( v < w )
	   {
              flip ( v , w ) ;	// flip values
	   }
	}

	cc = 9999 ;  // Just to show that "passing by value" will not
		     // effect variable "control" in the calling program.

}
	
//////////////  Definition of function flip() ////////////////////////
//              Exchanging the values of its arguments

void flip ( int& v , int& w )
{
	int tmp ;
	tmp = v   ;
	v   = w   ;
	w   = tmp ; 
}