Friday, 30 March 2018

Access Control In Classes OR Access Modifiers

Access specifiers in C++ class defines the access control rules. C++ has 3 new keywords introduced, namely,

1. public
2. private
3. protected

These access specifiers are used to set boundaries for availability of members of class be it data members of  members or member functions

Access specifiers in the program, are followed by a colon. You can use either one, two or all 3 specifiers in the same class to set different boundaries for different class members. They change the boundary for all the declarations that follow them.

Public
 Public, means all the class members declared under public will be available to everyone. The data members functions declared public can be accessed by other classes too.
  Hence there are chances that they might change them. So the key members must not be declared public.

Private
  Private keyword, means that no one can access the class members declared private outside that class. If someone tries to access the private member , they will get a compile time error. By default class variables and member functions are private.

  class PrivateAccess
  {
   private:    // private access specifier
   int x;       // Data Member Declaration
   void display( );  //Member Function declaration
   }

Protected
  Protected, is the last access specifier, and it is similar to private, it makes class member inaccessible outside the class. But they can be accessed by any subclass of that class.

 class ProtectedAccess
 {
   protected:    // protected access specifier
   int x;           // Data Member Declaration
   void display( );   // Member Function declaration
   }
  

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