What are Virtual functions in C++ ?

webmaster — Fri, 19 Aug 2022 12:34:29 +0000

Virtual function is a member function which is re-defined by a derived class and declared within a base class.
When you refer to a derived class object using a reference or pointer to the base class, you can call a virtual function for that object and execute the derived class’s version of the function.
It ensures that the correct function is called for an object, regardless of the type of reference used for function call.
It is mainly used to achieve Run-time polymorphism.
In base class functions are declared with a virtual. At run time the resolving of function call is done.

Sample Code

using namespace std;
 
class base {
public:
    virtual void print()
    {
        cout << "print base class\n";
    }
 
    void show()
    {
        cout << "show base class\n";
    }
};
 
class derived : public base {
public:
    void print()
    {
        cout << "print derived class\n";
    }
 
    void show()
    {
        cout << "show derived class\n";
    }
};
 
int main()
{
    base *bptr;
    derived d;
    bptr = &d;
 
    // Virtual function, binded at runtime
    bptr->print();
 
    // Non-virtual function, binded at compile time
    bptr->show();
   
    return 0;
}

virtual and pure virtual function in c++ - Wikitechy

What are Virtual functions in C++ ?

Sample Code

Output