Question

1. Provide a definition for the term abstraction. Give an example in the context of programming 2. In object oriented programming, composition and inheritance are both methods for reusing existing code. What are the differences between them. Provide an example where each one can/should be uscd. 3. If you are tasked with developing a program to keep track of NBA teams and games, what objects would you use? For every team, we would like to keep track of the players that are on that team, and for every game, we want to know who the teams were and what was the score. Remember, we want to work with objects from the problem space, not stings and integers.

Answer 1

1. Abstraction can be simply defined as hiding necessary information.

or

Abstraction is selecting data from a larger pool of data to show only the relevant details to the object. It helps to reduce programming complexity and effort.

Example : Classes in c++

classes in c++ can decide which data member will be visible and which will be not. example members declared as public can be accessed from anywhere whereas members declared as private can be accessed only within the class.

2. the main difference between composition and inheritance is :

composition allows us to reuse code without extending the class whereas inheritance needs to extend the class in order to reuse the code.

composition allows us to reuse code even for final class which is not extensible whereas inheritance doesn't allow in such cases.

Examples:

Inheritance :

class Fruit {

//... }

class Apple extends Fruit {

//... }

composition :

class Fruit {

//... }

class Apple {

private Fruit fruit = new Fruit(); //... }

3. declare two classes with Teams & Games. then declare n objects as n teams like Team 1,Team 2......etc, and store the attributes of each team i.e players of the team. similarly in game class declare all n games and store their respective attributes such as which two teams played the game and their scores.

you can take the below program for reference:

public class Dog

{

    // Instance Variables

    String name;

    String breed;

    int age;

    String color;

  

    // Constructor Declaration of Class

    public Dog(String name, String breed,

                   int age, String color)

    {

        this.name = name;

        this.breed = breed;

        this.age = age;

        this.color = color;

    }

  

    // method 1

    public String getName()

    {

        return name;

    }

  

    // method 2

    public String getBreed()

    {

        return breed;

    }

  

    // method 3

    public int getAge()

    {

        return age;

    }

  

    // method 4

    public String getColor()

    {

        return color;

    }

  

    @Override

    public String toString()

    {

        return("Hi my name is "+ this.getName()+

               ".\nMy breed,age and color are " +

               this.getBreed()+"," + this.getAge()+

               ","+ this.getColor());

    }

  

    public static void main(String[] args)

    {

        Dog tuffy = new Dog("tuffy","papillon", 5, "white");

        System.out.println(tuffy.toString());

    }

}