/* Code for exercise 5.4. |  | "C++ Solutions--Companion to The C++ Programming Language, Third Edition" | by David Vandevoorde; Addison-Wesley 1998; ISBN 0-201-30965-3. | | Permission to use, copy, modify, distribute and sell this software | and its documentation for any purpose is hereby granted without fee. | The author makes no representations about the suitability of this | software for any purpose.  It is provided "as is" without express or | implied warranty. `----------------------------------------------------------------------*/#include <iostream>void swap_values(int *p1, int *p2) {   int tmp = *p1;   *p1 = *p2;   *p2 = tmp;}void swap(int &v1, int &v2) {   int tmp = v1;   v1 = v2;   v2 = tmp;}int main() {   int a = 3, b = 27;   std::cout << "Initially:\n";   std::cout << "a = " << a << "  b = " << b << '\n';   swap_values(&a, &b);   std::cout << "After swap_values:\n";   std::cout << "a = " << a << "  b = " << b << '\n';   swap(a, b);   std::cout << "After swap:\n";   std::cout << "a = " << a << "  b = " << b << '\n';}