Comments on: Why do I need inheritance in OOP? Real-world examples.

By: dude

dude — Thu, 01 Dec 2011 17:41:46 +0000

what is missing in your example, and what is on the main reasons to have polymorphism in the first place is this class:

public class PetTrainer {
public void makeMyPetTalk(Pet p) {
p.say();
}
}

As you can see, PetTrainer can make any Pet talk – cats, dogs or even tigers that might come in the future.

By: Artem

Artem — Mon, 28 Nov 2011 08:14:19 +0000

Awaisdar:
The reason why the same code won’t work without correction in C# is the following:
in Java all methods are virtual by default, compare to C# where in order to make them virtual you have to specify “virtual” keyword. The following program is C# version of the example code:

using System;

namespace Test
{
public class Pet {
public virtual void say() { }
}

public class Dog : Pet {
public override void say() { Console.WriteLine(”I am a dog.”); }
}

public class Cat : Pet {
public override void say() { Console.WriteLine(”I am a cat.”); }
}

class Program
{
static void Main(string[] args)
{
Pet pet1 = new Dog();
Pet pet2 = new Cat();
pet1.say();
pet2.say();
Console.ReadKey();
}
}
}

By: awaisdar

awaisdar — Fri, 25 Nov 2011 04:03:02 +0000

in c# after
Pet pet1 = new Dog();
cat pet22 = new cat();
when i called
pet1.say();// it shows the say method of Pet class not of dog class.
and pent22.say();//shows the Cat class’s say method.

???????????????????

By: Vlad Z (AX guy from Kharkov)

Vlad Z (AX guy from Kharkov) — Wed, 31 Aug 2011 16:45:34 +0000

I was skimming through the comments people say and, in fact, this is a quite good and simple example of why to use so-called Liskov principle. You can always generally call Pet->say() via Pet base-class pointer not caring what subclass it actually represents (Dog, Cat or Bird). This is good and right practice in OOP.

http://en.wikipedia.org/wiki/Liskov_substitution_principle

By: shaan rizvi

shaan rizvi — Thu, 21 Jul 2011 03:28:33 +0000

you have need explanation of this topic with the help of daily life example……….

By: Manzoor

Manzoor — Thu, 17 Feb 2011 06:12:46 +0000

Its simple and need more explanation.

By: Manzoor

Manzoor — Thu, 17 Feb 2011 06:11:44 +0000

You are actually explaining about Dynamic Method Dispatch. Its is better if you go for any Real time Implementations of Inheritance.

By: Girish

Girish — Sun, 21 Feb 2010 07:17:05 +0000

The Article is quiet good and useful, but need to be explained in depth by giving more real world exmples

By: Alex

Alex — Sun, 25 Oct 2009 03:33:20 +0000

You are actually giving examples of polymorphism, which is achived via inheritance (http://en.wikipedia.org/wiki/Type_polymorphism)