Friend Function

 

Friend function:

A friend function is a non member function which can access the private, protected members of the class.

Syntax:

friend return_type function_name(arguments);

Characteristics of Friend Function.

·       Friend function is a non member function which can access private, protected members of the class.

·       Friend functions are declared inside the class by using keyword friend.

·       This function is defined outside the class without using keyword friend and scope resolution operator.

·       Friend functions are invoked like a non member function.

·       Arguments of these functions are objects.

·       A class can have more than one friend function.

·       A friend function can friend to more than one class.

Example:

class simple

{

            private:

                        int a;

            public:

                        void input();

                        void display();

                        friend void square(simple);

};

void simple::input()

{

            cin>>a;

}

void simple::display()

{

            cout<<a;

}

void square(simple x)

{

            a=x.a*x.a;

}

void main()

{

            simple m,n;

            m.input();

            n=add(m);

            n.display()

}