C++ Abstraction

Advantages of Data Abstraction

• Implementation details of the class are protected from the unexpected user-level errors, which corrupt the state of the object.
• It helps to avoids the code duplication.
• It helps to reuse the code and provide partitioning of the code across the classes.

Abstract Class

A class which consists atleast one pure virtual function is called an abstract class.

A Pure Virtual Function can be declared by equating it to zero.

An abstract class is used as a base class for the deriving purpose only. An abstract class can't create an object.

Example:

#include <iostream>     
using namespace std;  

 class A   
{    
    public:   
    virtual void show()=0;    
};    
 class B : A    
{    
    public:  
     void show()    
    {    
        cout << "Derived Class B" <<endl;    
    }    
};    
class C : A    
{    
    public:  
     void show()    
    {    
        cout << "Derived Class C" <<endl;    
    }    
};    
int main( ) {  
    B b;  
    C c;  
    b.show();
    c.show();
    return 0;  
}