What are the significances of Virtual Functions?

[sachin16]

Hey guys,
can anyone tell me what are the significances of virtual functions in C++?

[Banfa]

a virtual function is one where it is expected that a sub-class will over-ride the function. By declaring it virtual even if the function is envoked using a pointer to the classes base class the function in the sub class will be called

class BaseClass
{
public:
    virtual void printMe(){ puts("I am the Base Class");}
};
 
class DerivedClass : public BaseClass
{
public:
    void printMe(){ puts("I am the Derived Class");}
};
 
int main()
{
    DerivedClass dc;
    BaseClass *pbc = &dc;
 
    pbc->printMe();
 
    return 0;
}
 

This outputs

I am the Derived Class

without the virtual keyword it would output

I am the Base Class