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Overriding

Understand high-level programming concepts (such as inheritance, encapsulation, data abstraction, and polymorphism) and how they are implemented. 

Level 2 Programming theory

Joy Horvath

Instructional Designer

U_Intermediate_9_Overriding.mp4

How to override a base class's members with the members of a child class. 

Games

Explain how abstraction is used to expose only necessary script components

Explain how inheritance is used to share functionality between a parent and child class

Define the relationship between a parent and child class, including what a child class can and cannot do with respect to its parent class

Recognize opportunities where inheritance could be used to simplify code

Describe how polymorphism can be applied at compile time (method overloads) and run time (method overrides)

Explain how polymorphism is used to modify parent class functionality in a child class

Explain how encapsulation is used to write code that can only be used as intended by the programmer

Recommend a high-level system architecture for a given project 

Simplify code and make it reusable by correctly implementing the principles of inheritance and polymorphism

Intermediate Scripting

using UnityEngine;
using System.Collections;

public class Fruit 
{
    public Fruit ()
    {
        Debug.Log("1st Fruit Constructor Called");
    }

    //These methods are virtual and thus can be overriden
    //in child classes
    public virtual void Chop ()
    {
        Debug.Log("The fruit has been chopped.");        
    }

    public virtual void SayHello ()
    {
        Debug.Log("Hello, I am a fruit.");
    }
}


using UnityEngine;
using System.Collections;

public class Apple : Fruit 
{
    public Apple ()
    {
        Debug.Log("1st Apple Constructor Called");
    }

    //These methods are overrides and therefore
    //can override any virtual methods in the parent
    //class.
    public override void Chop ()
    {
        base.Chop();
        Debug.Log("The apple has been chopped.");        
    }

    public override void SayHello ()
    {
        base.SayHello();
        Debug.Log("Hello, I am an apple.");
    }
}


using UnityEngine;
using System.Collections;

public class FruitSalad : MonoBehaviour 
{    
    void Start () 
    {
        Apple myApple = new Apple();

        //Notice that the Apple version of the methods
        //override the fruit versions. Also notice that
        //since the Apple versions call the Fruit version with
        //the "base" keyword, both are called.
        myApple.SayHello();
        myApple.Chop();    

        //Overriding is also useful in a polymorphic situation.
        //Since the methods of the Fruit class are "virtual" and
        //the methods of the Apple class are "override", when we 
        //upcast an Apple into a Fruit, the Apple version of the 
        //Methods are used.
        Fruit myFruit = new Apple();
        myFruit.SayHello();
        myFruit.Chop();
    }
}


Overriding

1. Overriding

Complete this tutorial