Question

Java programming: please help with the following assignment: Thank you.

Create a class called GiftExchange that simulates drawing a gift at random out of a box.

The class is a generic class with a parameter of type T that represents a gift and where T can be a type of any class. The class must include the following

1. An ArrayList instance variable that holds all the gifts,The ArrayList is referred to as theBox.
2. A default constructors that creates the box.
3. An add method that adds a gift to the box.
4. A drawGift method that
   1. Ensure the box is not empty, if it is empty returns null.
   2. If not empty
      1. Selects a gift at random from the Box.
      2. Removes that gift from the Box
      3. Returns the selected gift.
5. A toString method that returns a nicely formatted String representing all the object in the ArrayList. Assume any object stored in the ArrayList have a toString method.
6. You may add any other method(s) you think you need however no additional functionality is required.

No Javadoc or import statements required

Answer 1

import java.util.ArrayList;
import java.util.Random;

class GiftExchange<T>{
    ArrayList<T> gifts;
    GiftExchange(){
        gifts = new ArrayList<>();
    }
    public void add(T gift){
        gifts.add(gift);
    }
    public T drawGift(){
        if(gifts.isEmpty()){
            return null;
        }
        Random r = new Random();
        int ind = r.nextInt(gifts.size());
        T ans = gifts.remove(ind);
        return ans;
    }

    @Override
    public String toString(){
        String ans = "Gifts : ";
        for(T t : gifts){
            ans = ans+t+" ";
        }
        return ans;
    }
}

class Main{
    public static void main(String[] args) {
        GiftExchange<Integer> cards = new GiftExchange<>();
        cards.add(50);
        cards.add(49);
        cards.add(60);
        System.out.println(cards);
        System.out.println("Gift drawn : "+cards.drawGift());
    }
}

OUTPUT :

Run Main C:\Program Files \Java\jdk1.8.0_1311binljava" . Gifts 50 49 60 Gift drawn : 60 Process finished with exit code 0