CODEWITHSUNDEEP
c#
Bob
Bob

Reputation: 783

Polymorphism in C#. Explain output

I expected output C in this program. But real result is A.
Please, explain why program prints A. 

class A 
{
    public virtual void  say() 
    {
        Console.WriteLine ("A");
    }
}

class B : A
{
    public new virtual void say() 
    {
        Console.WriteLine ("B");
    }
}

class C : B 
{
    public override void say() 
    {
        Console.WriteLine ("C");
    }
}

class MainClass
{
    public static void Main (string[] args)
    {
        A a = new C ();
        a.say();
    }
}

Upvotes: 2

Views: 75

Answers (2)

Dmitry
Dmitry

Reputation: 14059

It's because you created new virtual method say() in the class B.
This new method hides original method A.say(), so in the class C you overriden this new method B.say() but not the A.say().

And since you declared your object as A

A a = new C ();

the old A.say() method is called.

Upvotes: 3

Tim Snow
Tim Snow

Reputation: 345

You're not overriding the say method in Class B, which is the sub class of Class C. 

   public new virtual void say()

In the above line, you're hiding the say method. Look at the new modifier here on MSDN

Upvotes: 2

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