Question

I have these classes:

class A
 {
    public int Foo()
    {
        return 5;
    }
}

class B : A
{
    public int Foo() 
    {
        return 1; 
    }
}

and I use them like this:

        B b = new B();
        int x = b.Foo();

and although Foo() in the base class isn’t virtual, or in the derived class – it hasn’t the override keyword, still x equals 1. Then, what is the use of the virtual and override keywords?

Answer 1

Polymorphism allows type B to be treated as type A.

A b = new B();
int x = b.Foo(); // x will be 1 if virtual, 5 if not.