#include <iostream>
using namespace std;

void noswap( int v1, int v2 ){
  int tmp = v2;  v2 = v1;  v1 = tmp;
}
void rswap( int& v1, int& v2 ){
  int tmp = v2;  v2 = v1;  v1 = tmp;
}
void pswap( int* v1, int* v2 ){              // assumed in text
  int tmp = *v2;  *v2 = *v1;  *v1 = tmp;
}

int main() {
  int i=1, j=2;
  noswap( i,  j );  cout << i << ", " << j << endl;
  rswap(  i,  j );  cout << i << ", " << j << endl;
  pswap( &i, &j );  cout << i << ", " << j << endl;
  return 0;
}