#include <iostream>
using namespace std;

void swapval(int,int);
void swapref(int &, int &);
void swapptr(int *, int *);


void main(){
	int x = 3, y = 7;
	cout << " preswap x,y "  << x << " " << y << endl;
	swapval(x,y);
	cout << " postswap x,y "  << x << " " << y << endl;
	cout << " preswap x,y "  << x << " " << y << endl;
	swapref(x,y);
	cout << " postswap x,y "  << x << " " << y << endl;
	cout << " preswap x,y "  << x << " " << y << endl;
	swapptr(&x,&y);
	cout << " postswap x,y "  << x << " " << y << endl;
}

void swapval(int a, int b){
	int t = a;
	a = b;
	b = t;
	cout << " swapval a,b "  << a << " " << b << endl;
}

void swapref(int &a, int &b){
	int t = a;
	a = b;
	b = t;
	cout << " swapref a,b "  << a << " " << b << endl;
}

void swapptr(int *a, int *b){
	int t = *a;
	*a = *b;
	*b = t;
	cout << " swapptr a,b "  << *a << " " << *b << endl;
}