Thread: Virtual Keyword

I have doubt using the keyword "virtual". In C++ if I create a pure virtual function then the derived class has to implement it. If the derived class does not declare the pure virtual function with the keyword "virtual" the MVC++ does not warn me about it. But if I had the keyword virtual in the derived class it still doesn't make any difference.

Here is a sample code:

Code:

class A  
{
public:
	 A();
	 virtual ~A();
	 virtual void A::op() = 0;
 
};
 

class B : public A  
{
public:
	 B();
	 virtual ~B();
	 void op(); // doesnt make any difference if I have virtual or don't have it.
 
};

I want to know if there is any difference using / not using the virtual keyword?