example4.cpp

Advanced Internet Programming Lecture 2 C/C++ Review Li,Suke School of Software and Microelectroni

#include <iostream>
using namespace std;

class myclass {
  int a, b;
public:
  friend int sum(myclass x);
  void set_ab(int i, int j);
};

void myclass::set_ab(int i, int j)
{
  a = i;
  b = j;
}

// Note: sum() is not a member function of any class.
int sum(myclass x)
{
  /* Because sum() is a friend of myclass, it can
     directly access a and b. */

  return x.a + x.b;
}

int main()
{
  myclass n;

  n.set_ab(3, 4);

  cout << sum(n);

  return 0;
}