Question: What Is A Friend Function In C ++?

What is a friend function Why do we use it?

In object-oriented programming, a friend function, that is a “friend” of a given class, is a function that is given the same access as methods to private and protected data.

A friend function is declared by the class that is granting access, so friend functions are part of the class interface, like methods..

What is the advantage of friend function in C++?

One advantage of the friend function or class is that we can access the private and protected data of the class. For Example, if we are implementing a linked list, then we can make the linked list class as a friend of the node class and access its data as the linked list consists of nodes.

Which rule will not affect the friend function?

In principle, private and protected members of a class cannot be accessed from outside the same class in which they are declared. However, this rule does not affect friends.

What is a friend function and what are its advantages?

What are advantages of using friend classes? – The friend function is a ‘non member function’ of a class. It can access non public members of the class. A friend function is external to the class definition. … Allows sharing private class information by a non member function.

What is a friend function What are the merits and demerits of friend function?

What are the merits and demerits of friend function? A friend function is the friend of the given class which can access all the public, private and protected variables of that class in which it is declared. … It is able to access members without need of inheriting the class.

What is friend function and friend class explain with example?

As we know that a class cannot access the private members of other class. Similarly a class that doesn’t inherit another class cannot access its protected members. Friend Class: A friend class is a class that can access the private and protected members of a class in which it is declared as friend.

What is a friend function in C++?

A friend function of a class is defined outside that class’ scope but it has the right to access all private and protected members of the class. … A friend can be a function, function template, or member function, or a class or class template, in which case the entire class and all of its members are friends.

What is friend function and its characteristics?

Characteristics of a Friend function: The function is not in the scope of the class to which it has been declared as a friend. … It can be invoked like a normal function without using the object. It cannot access the member names directly and has to use an object name and dot membership operator with the member name.

What is the difference between friend class and friend function?

A friend function is used for accessing the non public member of a class. A class can allow non-member function and other classes to access its own private data by making them friend A Friend class has full access of private data members of another class without being member of that class.

What are the advantages and disadvantages of friend function in C++?

Thus the ability to choose between member functions ( x.f() ) and friend functions ( f(x) ) allows a designer to select the syntax that is deemed most readable, which lowers maintenance costs. The major disadvantage of friend functions is that they require an extra line of code when you want dynamic binding.

What is virtual function explain with example?

– A virtual function is a member function that is declared within a base class and redefined by a derived class. When a class containing virtual function is inherited, the derived class redefines the virtual function to suit its own needs. … – Base class pointer can point to derived class object.

Can friend function be inherited?

In C++, friendship is not inherited. If a base class has a friend function, then the function doesn’t become a friend of the derived class(es). For example, following program prints error because show() which is a friend of base class A tries to access private data of derived class B.

What is the use of virtual function?

A virtual function is a member function that you expect to be redefined in derived classes. When you refer to a derived class object using a pointer or a reference to the base class, you can call a virtual function for that object and execute the derived class’s version of the function.

What is the use of friend class?

Friend Class A friend class can access private and protected members of other class in which it is declared as friend. It is sometimes useful to allow a particular class to access private members of other class. For example a LinkedList class may be allowed to access private members of Node.

What is pure virtual function and what is its use?

A pure virtual function is a function that must be overridden in a derived class and need not be defined. A virtual function is declared to be “pure” using the curious =0 syntax. For example: class Base {

What are pure virtual functions?

A pure virtual function or pure virtual method is a virtual function that is required to be implemented by a derived class if the derived class is not abstract. Classes containing pure virtual methods are termed “abstract” and they cannot be instantiated directly.

Is it necessary to pass argument in a friend function?

It is possible, to have a friend function with no arguments. It Seldom used. Of course it is possible.

What are virtual functions write an example?

Example 2: C++ virtual Function DemonstrationWhen print(animal1) is called, the pointer points to an Animal object. So, the virtual function in Animal class is executed inside of print() .When print(dog1) is called, the pointer points to a Dog object. … When print(cat1) is called, the pointer points to a Cat object.