Virtual Functions ????

[Patrick]

Please explain the concept of virtual functions using a simple example and how its working is different from that of normal functions . Is there any special syntax for declaring these functions except the use of keyword Virtual

[v0id]

// Making an interface for deriving classes
class Base
{
    public:
        // Deriving classes have to override the following function
        virtual void foo() = 0;
};

// A class deriving from the base class
class Derived
    : public Base
{
    public:
        // Overrides and implements the function now
        void foo() { /* do something... */ }
};

// ...

Derived *dObj = new Derived;
// Use it in some way
delete dObj;