What's a good example for class inheritance? [closed]

Answer 1

Auto Parts can be interesting for example you might have

class part
{
    OEM
    Manufacturer
    Number
    Description
}

class Tire extends Part
{
   Speed
   Rating

}

Answer 2

You can find good examples of class inheritance in design-patterns.

1. Abstract_factory_pattern : Provides a way to encapsulate a group of individual factories that have a common theme without specifying their concrete class

2. Template_method_pattern: It is a behavioral design pattern that defines the program skeleton of an algorithm in an operation, deferring some steps to subclasses.

3. Decorator_pattern: It is a design pattern that allows behavior to be added to an individual object, either statically or dynamically, without affecting the behavior of other objects from the same class

Refer to below posts for real world examples:

When to Use the Decorator Pattern?

Template design pattern in JDK, could not find a method defining set of methods to be executed in order

Answer 3

I agree with Jon Skeet on his streams example. Perhaps it's not perfect, but it has one advantage over most of of the examples here:

It is realistic

Bicycles, persons or animals, shapes or weapons just wouldn't be modelled by inheritance in real projects. (shapes in particular, are downright dangerous, because it doesn't work.)

That's my pet peeve with inheritance. It is too often taught as something that must be used to express every hierarchy you can find. An employee is a person, right? So the Employee class must inherit from a Person class. But a person is also a LivingCreature, so we'd better have one of those classes too. And a LivingCreature is also an Organism, so there we have another class. And an Organism is.... feel free to continue.

I think it'd be nice if someone, somewhere, actually taught inheritance by explaining when it should be used, and not just how you can force it down over any hierarchy, whether it's beneficial or not.

Streams (or devices as in ChrisW's example) have the advantage that they make sense. You want to be able to treat all streams the same, whether they're connected to a memory buffer, a file or a network socket. And all hardware devices do have a lot of behavior in common that could plausibly be factored out into a Device base class.

Answer 4

I think Shape is a good abstract class. There are both 2D and 3D shapes. The 2D shapes typically have area while 3D shapes have volume. Both can have a "location" or "mass center".

Some suggestions:

class Shape {..}

class Shape2D extends Shape {...}

class Circle extends Shape2D {...}

class Rectangle extends Shape2D {...}

class Polygon extends Shape2D {...}

class Shape3D extends Shape {...}

class Sphere extends Shape3D {...}

Answer 5

If you are into video games could be something like this:

class enemy{
  Health
  Posx
  posy
  Etc
}

class orc : extends enemy{
 speed
 Strength
 etc
}

Answer 6

The best example that i have came across (and read in many books) is the one that uses Shape.

The best thing about this is that you can very easily explain all the concepts (including the tough ones ) related to OOPs like Class,Object,Inheritance,Abstraction,Encapsulation,Polymorphism,etc to any programmer irrelevant of his experience.