To implement Friend Class

#include<iostream.h>
#include<conio.h>

 class boy
 { private:
   int income1,income2;
   public:
   void setdata(int n1,int n2)
   { income1=n1;
     income2=n2;
   }
   friend class girl;
 };

 class girl
 { int income;
   public:
   int g_fun(boy b1)
   { return b1.income1+b1.income2;  }

   void set_data(int n)
   { income=n; }

   void show()
   { boy b1;
     b1.setdata(300,500);
     cout<<"\n\n  boy income = "<<b1.income1;
     cout<<"\n\n  girl income = "<<income;
   }
 };

  void main()
  { boy b1;
    girl g1;
    clrscr();
    b1.setdata(100,200);
    g1.set_data(300);
    g1.show();
    cout<<"\n\n  The total income of boy "<<g1.g_fun(b1);
    getch();
  }