CODEWITHSUNDEEP
javaclassvariablesmethods
Aurora Rossi
Aurora Rossi

Reputation: 53

Java method that tries to change a variable isn't working

I am currently coding this bit of a game in which, an enemy (a bat) should have its health drop but it's not working.

class BatTest{
public static void main(String args[]) {
    String input = "";
    boolean exit = false;
    Bat bat1 = new Bat();
    Inventory MainInv = new Inventory();
    MainInv.smallknife = true;
    System.out.println("A bat has appeared!");
    System.out.println("Health: " + bat1.health + " Attack Strength: " + bat1.damage);
    do{
        System.out.println("Health: " + bat1.health + " Attack Strength: " + bat1.damage);
        System.out.print("What would you like to do: ");
        input = Keyboard.readString();
        if (input.equalsIgnoreCase("Attack")) {
            Abilities.smallknifeMA(bat1.health);
            System.out.println(bat1.health);
        }
        else if (input.equalsIgnoreCase("exit")) {
            exit = true;
        }
    }while(!exit);
}

}

//enemyH denotes the health of the enemy

class Abilities {
static double smallknifeMA(double enemyH) {
    enemyH = enemyH - 2.0;
    return enemyH;
}

}

class Inventory {
boolean smallknife;
boolean startlockerkey;

}

I can't really understand why smallknifeMA doesn't lower the variable bat1.health.

Thanks, Aurora

Upvotes: 0

Views: 60

Answers (1)

Elliott Frisch
Elliott Frisch

Reputation: 201399

Java is not pass by reference. This

Abilities.smallknifeMA(bat1.health);

needs to update bat1.health. Something like,

bat1.health = Abilities.smallknifeMA(bat1.health);

Or, modify smallknifeMA to take a Bat argument and update the health directly. Something like,

static void smallknifeMA(Bat bat) {
    bat.health -= 2.0;
}

However, it is a bad practice to make your class members public; you should probably encapsulate this behaviour in Bat.

Upvotes: 3

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