method doesn't finish running - works infinitly

Question

I tried to write simple program and stuck at some point into while loop.

From current output I see that it only print the same data.

But it should be executed at every iteration.

Snippet of code:

public void fight(Droid first, Droid second) {

        while (first.isAlive() & second.isAlive()) {

            if ((random.nextInt(10) + 1) % 2 == 0) {
                shoot(first, second);
            } else {
                shoot(second, first);
            }

            // testing output
            System.out.printf("Droid %s has %d power level%n", first.getName(), first.getPower());
            System.out.printf("Droid %s has %d power level%n", second.getName(), second.getPower());
        }

        if (first.getPower() <= 0) {
            fightResult(second);
        } else {
            fightResult(first);
        }
    }

And here is output:

Droid John has 5 power level
Droid Dik has 8 power level
Droid John has 5 power level
Droid Dik has 8 power level
Droid John has 5 power level
Droid Dik has 8 power level
Droid John has 5 power level
Droid Dik has 8 power level

I made some silly mistake and couldn't find one.

Update:

here is shoot():

private void shoot(Droid first, Droid second) {
    second.setPower(first.getImpact());
}

and Droid class:

public abstract class Droid {

    protected Random random;
    private String name;
    private int power;
    private int impact;

    public Droid(int aPower, int anImpact) {
        power = aPower;
        impact = anImpact;
    }

    public String getName() {
        return name;
    }

    public void setPower(int aPower) {
        power = aPower;
    }

    public void setImpact(int anImpact) {
        impact = anImpact;
    }

    public int getPower() {
        return power;
    }

    public int getImpact() {
        return impact;
    }

    public abstract void fight(Droid first, Droid second);

    public boolean isAlive() {
        boolean result = false;
        if (this.getPower() > 0) result = true;
        return result;
    }
}

• How to solve this trouble?

Answer 1

Your shoot method is incorrect, it keeps setting the droids to each other's impact value.

I suspect you'd want to subtract the impact from the droid's power instead.

Something along the lines of

private void shoot(Droid first, Droid second) {
    second.setPower(second.getPower() - first.getImpact());
}

or somewhat more OO-style:

first.shoot(second);

public void shoot(Droid second) {
    second.absorbImpact(getImpact());
}

public void absorbImpact(int impact) {
    power -= impact;
}