Challenges

Remember the rules for this are

• Try to use only the information given up to this point in this book.
• Try not to give up until you've given it a solid attempt

Challenge 1.

Replace the usage of a normal class in the following code with a record.

import java.util.Arrays;

class InventoryItem {
    String name;

    InventoryItem(String name) {
        this.name = name;
    }
}

class Main {
    void main() {
        var item1 = new InventoryItem("sword");
        var item2 = new InventoryItem("shield");
        var item3 = new InventoryItem("armor");

        InventoryItem[] items = {
            item1,
            item2,
            item3
        };

        IO.println(Arrays.toString(items));
    }
}

Challenge 2.

Make an instance of the Tien record and print it out.

enum TienMove {
    DODON_RAY,
    TRI_BEAM,
    EXPLODE
}

record Chiaotzu(
    Move memorableMove
) {}

record Tien(
    Chiaotzu onlyFriend,
    Move firstMove,
    Move secondMove
) {}

class Main {
    void main() {
        Tien tien;
        // CODE HERE
        IO.println(tien);
    }
}

Challenge 3.

What will this program output when run?

1. true then true
2. true then false
3. false then true
4. false then false

Write down your guess and then try running it.

class Position {
    int x;
    int y;

    Position(int x, int y) {
        this.x = x;
        this.y = y;
    }
}

record Location(int x, int y) {}

class Main {
    void main() {
        var p1 = new Position(7, 1);
        var p2 = new Position(7, 1);
        IO.println(p1.equals(p2));

        var l1 = new Location(8, 3);
        var l2 = new Location(8, 3);
        IO.println(l1.equals(l2));
    }
}