C++ Friends

What is a friend function/ class?

• A friend is permitted full access to private and protected members.
• A friend can be a function.
• A friend can be an entire class. In this case all member functions of the class are given access.

EXAMPLE: Demonstrate the usage of friend function

#include <iostream>

using namespace std;

class Check {
        int data;
    public:
        Check() {
           data = 10;
        }

        friend void MyFunc(Check c);
};

void MyFunc(Check c) {
    cout << c.data << endl;
}

void main()
{
    Check c;
    MyFunc(c);
}

EXAMPLE: Demonstrate the usage of friend classes

#include <iostream>

using namespace std;

class One {
    int data;
    public:
    One() {
        data = 10;
    }

    friend class Two;
};

class Two {
    public:
    void AccessOne(One obj) {
        cout << obj.data << endl;
    }
};

void main()
{
    One obj1;
    Two obj2;
    obj2.AccessOne(obj1);
}