C++ | Friend function 14

“Friend function is a special function which has the capability to access the private data elements of two or more objects, the objects may belong to the same or different classes.”

Syntax:
friend return_type function_name(parameters);
where:
friend:
is a keyword used to declare a friend function.
return_type:
type of value the function is returing back
function_name():
Name of the friend function , it is a user defined name
parameters:
list of parameters passed to the friend function , if passed.

Properties
1. A friend function is declared using the keyword “friend”.
2. Friend function has to be declared in all the classes whose private data elements are to be accessed.
3. The declaration of friend function in each class whose private data elements are to be accessed has to be exactly the same.
4. There will be a common definition of the friend function and it is shared by all the objects.
5. While giving the definition of friend function keyword “friend” is not used.
6. While giving the definition of friend function the reference of a class is not given.
7. Within the definition of friend function, the data elements of the object are accessed using dot (.) operator.
8. While calling a friend function we do not require an object of the class. i.e. a friend function is invoked without using as an object.
9. There can be any number of friend functions in a class.

* While giving the definition of friend function the reference of class is not given.

* While calling a friend function we do not require an object of the class. i.e. a friend function is invoked without using an object.

1. Private data of other classes can be accessed using friend functions.

2. The scope of friend function is not limited to the class in which it is declared.

3. It can be invoked like a normal function without the help of the object and dot operator.

4. A friend function can be used to increase the versatility of the overloaded operators.

5. The values of the private members of a class can be altered by friend function.

6. The friend function is used to bridge, classes when the function operates on the objects of two different classes.