// Swapping - interchange the values of two variables a and b.
// illustration by bds 11/98
#include <iostream.h>

// no references or pointers, only swaps locally, fails the intention of swap.
template <class T>
void swap1( T x, T y ) {
  cout << "  x = " << x << " and y = " << y << " entering swap1" << endl;

  T tmp = x;
  x = y;
  y = tmp;

  cout << "  x = " << x << " and y = " << y << " exiting swap1" << endl;
}

// swapping using pointers
template <class T>
void swap2( T* x, T* y ) {
  cout << "  x = " << *x << " and y = " << *y << " entering swap1" << endl;

  T tmp = *x;
  *x = *y;
  *y = tmp;

  cout << "  x = " << *x << " and y = " << *y << " exiting swap1" << endl;
}

// swapping using references
template <class T>
void swap3( T& x, T& y ) {
  cout << "  x = " << x << " and y = " << y << " entering swap1" << endl;

  T tmp = x;
  x = y;
  y = tmp;

  cout << "  x = " << x << " and y = " << y << " exiting swap1" << endl;
}


int main() {
   int a = 1;
   int b = 2;
   cout << "a = " << a << " and b = " << b << " before swap1" << endl;
   swap1(a, b);
   cout << "a = " << a << " and b = " << b << " after swap1" << endl;
   swap2(&a, &b);
   cout << "a = " << a << " and b = " << b << " after swap2" << endl;
   swap3(a, b);
   cout << "a = " << a << " and b = " << b << " after swap3" << endl;
}