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Java Java Objects Harnessing the Power of Objects Throwing Exceptions

Mike McKnight
Mike McKnight
6,717 Points
Posted by Mike McKnight
Mike McKnight
6,717 Points

Throwing Exception before change

It says I need to throw my exception before my change of lapsDriven. I attempted to put: int barsLeft = barCount -= laps; if (barsLeft<MIN_BARS); throw new IllegalArgumentException("Out of Fuel"); before it and it came up with a compiling error saying it was unreachable.

GoKart.java 
class GoKart {
  public static final int MAX_BARS = 8;
  public static final int MIN_BARS=1;
  private String color;
  private int barCount;
  private int lapsDriven;

  public GoKart(String color) {
    this.color = color;
  }

  public String getColor() {
    return color;
  }
  public void charge() {
    barCount = MAX_BARS;
  }

  public boolean isBatteryEmpty() {
    return barCount == 0;
  }

  public boolean isFullyCharged() {
    return MAX_BARS == barCount;
  }

  public void drive() {
    drive(1);
  }

  public void drive(int laps) {
    lapsDriven += laps;
    barCount -= laps;
    int barsLeft = barCount -= laps;
      if (barsLeft<MIN_BARS);
      throw new IllegalArgumentException("Out of Fuel");
  }
}

2 Answers

markmneimneh
markmneimneh
14,132 Points
markmneimneh
markmneimneh
14,132 Points

Your code will not work ....

this is a pseudo code to consider

lapsDriven += laps;
barCount -= laps;
      if (barCount <MIN_BARS);
          throw new IllegalArgumentException("Out of Fuel");
     else
          barsLeft =   barCount - MIN_BARS ; // or whatever lower limit the challenge is setting

...
...
and so on

it been a long time since I too this particular challenge ... but please note the logic in the pseudo code

Brian Pedigo
Brian Pedigo
26,783 Points
Brian Pedigo
Brian Pedigo
26,783 Points

Hi Mike it looks like you are updating your variables before you validating if they should be. First increment lapsDriven. Second set a check point (if statement) to see if the battery is empty, if the battery is empty throw the argument, otherwise lower the barCount by 1. I hope this helped! 

  public void drive(int laps) {
    lapsDriven += laps;  
    if(isBatteryEmpty()){
      throw new IllegalArgumentException;
    } else {
    barCount -= laps;
    }
  }