Access Specifier in C++

Access Specifiers In C++

•  In object oriented programming , access specifiers are used .The access specifier refers to accessibility of the variable in a class . Depending upon the type of access specifier , the accessibility of a variable is decided.

     There are three types of access specifier in C++.

• Public access specifier.

• Private access specifier.

• Protected access specifier.

• Public Access Specifier :
• When public access specifier is written before a variable , then the variable can be publicly accessed i.e the variable can be accessed inside the class as well as outside the class.

#include<iostream>

using namespace std;

class demo

{

       public:int i;//local variable of class

       public:void fun()//function of class

                {

                           cout<<i;

                }  

            

};

int main()

{

       demo obj;//object of class

       obj.i=10;

       obj.fun();

}  

  

•  In above example ,' int i ' is the variable and ' fun() ' is the function of class demo and it is accessible in the entire program due to the public access specifier.  

• Private Access Specifier :
• When private access specifier is written before class members ( variables and functions ) ,then the class members become private and thus,they can be accessed only inside the class.

#include<iostream>

using namespace std;

class demo

{

       private:int i;//local variable of class

       private:void fun()//function of class

                {

                           cout<<i;

                }  

            

};//end of class

int main()

{

       demo obj;//object of class

       obj.i=10;//error

       obj.fun();//error

}

• In above example , local variable ' int i ' and function ' fun() ' are having private access specifier , so it cannot be accessed outside the class.

Note:-When the class members have no access specifier , then they are private by default.

•  Protected Access Specifier : 
• When protected access specifier is used , the class members can be accessed inside the same class as well as in a derived class , But it cannot be accessed publicly.

#include<iostream>

using namespace std;

class demo

{

       protected:int i;//local variable of class

       protected:void fun()//function of class

                {

                           cout<<i;

                }  

            

};//end of class

int main()

{

       demo obj;//object of class

       obj.i=10;//error

       obj.fun();//error

} 

• In above example , local variable ' int i ' and function ' fun() ' are having protected access specifier , so it cannot be accessed outside the class.