What these two lines of code?

morteza siami

Hi.
What these two lines of code?
Which Class w() calls?
---------------------------
obj temp = new x();
temp.w();
--------------------------
please help me.

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes13y ago
Accepted answer
Sure, here's one. I've invented a new method 'm' to illustrate the difference between virtual and non-virtual methods:

using System;

class obj
{
public void w()
{
Console.WriteLine("Hello from obj.w");
}

public virtual void m()
{
Console.WriteLine("Hello from obj.m");
}
}

class x : obj
{
public override void m()
{
Console.WriteLine("Hello from x.m");
}
}

class Test
{
static void Main()
{
obj temp = new x();
temp.w();
temp.m(); // calls x's version
Console.ReadKey();
}
}

The output should be:

Hello from obj.w
Hello from x.m
morteza siami13y ago
Ok Vulpes. Fully understood. Thank you.
morteza siami13y ago
Sorry I,not Understand Please give me an example please.
Vulpes13y ago
It appears that 'obj' is the parent or an ancestor class of 'x' and that 'obj' contains a method 'w' which is therefore inherited by 'x'.

If 'w' is not virtual, then temp.w() will call 'obj's version.

If 'w' is virtual or abstract and is overridden within 'x', then temp.w() will call 'x's version because the runtime type of temp is 'x'.