Friend function in c++

Hello friends, in this post today, we learn about Friend function in c++ and how to use Friend function in c++. so lets start...

Friend function:-

Friend function as a friend of a class and can allow that friend function to access private and protected data members of that class.

Friend functions are mostly used where two or more classes want to share a common function.

Important points about Friend Function.

friend is a keyword. A friend function is created by placing the keyword friend in the function declaration but not in function definition. And function definition must be defined outside the class to which it is friend.

It is not a member function of the class but it have full access to the public, private and protected data member of the class.

A friend function is not a member function of the class and cannot be called from any object of the class using dot operator.

The arguments of friend functions are usually objects of the class to which it is a friend.

It should not be defined with membership label.

It cannot access the member names directly.

A friend function can be friend of more than one class.

A function of one class can be a friend of another class.

We can have whole class as a friend of another class.

We use friend function usually with multiple classes but can used with single class also.

A friend function can be declared in the public or private visibility mode without affecting its meaning.

There can be any number of friend functions of a class.

It is not in the scope of the class to which it has been declared as friend.

Syntax of friend function:-

class class_demo
{
   Access modifiers:
   data members;
   members functions;

  friend data_type function_name (parameters);  // friend function declaration
};

data_type function_name (parameters)  //definition
{
   function definition;
}

Example:

#include <iostream>
using namespace std;
class friend_fn
{
   public:
   int n;

   public:
   void input(int x)
    {
      n=x;
    }

    friend int square(friend_fn);
    friend int cube(friend_fn);
};


   int square(friend_fn f)
   {
     return f.n * f.n;
   }


int cube(friend_fn f)
   {
     return f.n*f.n*f.n;
   }


int main( )
{

  friend_fn F;
  F.input(6);
  cout<<"Square is="<<square(F)<<endl;;
  cout<<"cube is="<<cube(F)<<endl;
  return 0;
}

Output:-

Square is=36
cube is=216

I hope that whatever information I have given in this post today, you have liked it and you have understood it.so keep learning and wait for the next post that will help you to increase your knowledge with the something new information.

Thank you so much for reading. And take care about yourself and your family.

Comments

Inheritance in c++

Hello friends, in this post today, we learn about Inheritance in c++ concept and types of inheritance in c++ . Which is very important. so lets start... Inheritance Inheritance Class can acquire the properties and methods of another class. Inheritance is the process of deriving a new class from an already existing class. In other words" Inherit all the properties and methods of class into another class, is called Inheritance." Inheritance provides the idea of reusability i.e., code once written can be used again and again in number of new classes. The new class is called derived class and old class is called base class. The new class can use all or some of the features of the already existing class and the programmer can define his own members to the new class. Types of Inheritance In c++, there are 5 types of inheritance. Types of Inheritance Syntax of Inheritance:- class derived_classname : access_spacifier base_classname Where class is keyword used to create a clas

Constructor in c++

Hello friends, in this post today, we learn about what is constructor in c++ and types of constructor . so lets start... Constructor in c++ Constructor:- A constructor is a “special” member function which initializes the objects of class. Constructor is used to solve problem of initialization. Properties of constructor:- Constructors are used to construct the object of the class. Constructor name must be same as class name. Constructor is invoked automatically when objects of the class are created. The constructors are always declared in the public section. If declared in the private section then objects are can only be created inside the member functions but serve no purpose. It must be an instance member function , that is, it can never be static. Constructors do not have any return type not even void so they cannot return any value. Constructor can also be overloaded. Constructors cannot be inherited, but they can be called from the constructors of derived class . Constructor

What is scope resolution operator in c++

Hello friends, in this post today, we will learn about What is scope resolution operator in c++ and how to use in our program. so let's start.... Scope resolution operator Scope resolution operator :- Scope resolution operator which is also known as ( membership lable ), represnted as (::) . The scope resolution operator is employed to resolve or extend the scope of variable or functions. C++ is block structured language. We know that the same variable or function name can be used to have different meaning in different block. The scope resolution operator will refer value of worldwide variable or function from anywhere (also from inner block). Without scope resolution operator all variable will refer local value. Example for variabe: #include <iostream> using namespace std ; int m= 10 ; int main () { int m= 20 ; { int k=m; int m= 30 ; cout<< "we are in inner block \n " ; cout<< "k=" <<k<

Hustlers Knowledge

Search This Blog