Virtual functions in derived classes

1.8

In C++, once a member function is declared as a virtual function in a base class, it becomes virtual in every class derived from that base class. In other words, it is not necessary to use the keyword virtual in the derived class while declaring redefined versions of the virtual base class function.

Source: http://www.umsl.edu/~subramaniana/virtual2.html

For example, the following program prints “C::fun() called” as B::fun() becomes virtual automatically.

#include<iostream>

using namespace std;

class A {
  public:
    virtual void fun()
    { cout<<"\n A::fun() called ";}
};

class B: public A {
  public: 
    void fun() 
    { cout<<"\n B::fun() called "; }      
};

class C: public B {
  public:
    void fun()
    { cout<<"\n C::fun() called "; }      
};

int main()
{
   C c; // An object of class C
   B *b = &c; // A pointer of type B* pointing to c
   b->fun();  // this line prints "C::fun() called"
   getchar();
   return 0;
}

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above

GATE CS Corner    Company Wise Coding Practice

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.

Recommended Posts:



1.8 Average Difficulty : 1.8/5.0
Based on 34 vote(s)










Writing code in comment? Please use ide.geeksforgeeks.org, generate link and share the link here.