Friend Class

Code:

#include<iostream.h>

using namespace std;

class Sample
{
   int a;

public:

   Sample(int a)
   {
      this->a=a;
   }

   int getA()
   {
      return a;
   }

   friend class Test;
};

class Test
{

public:

   Test(Sample* obj,int a)
   {
      obj->a=a;
   }

};

int main()
{
   Sample s(20);
   Test t(&s,30);
   cout<<"Changed value of a : "<<s.getA();
}


Test is a friend class of Sample. So Test can access private members of Sample. In this example Test access private member 'a' of Sample.

I think a friend class can alos be used to access the protected member of the base class.

yes.. friend class can access all the members of the class.

In this example "Test" can access private, protected and public members of "Sample"