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Java Java Objects Harnessing the Power of Objects Throwing Exceptions

Adrian Bosada
Adrian Bosada
749 Points
Posted by Adrian Bosada
Adrian Bosada
749 Points

Learn Java>Objects>Exceptions>Quiz help!!!

I am getting this question wrong, but it says I need to throw the exception before I change the barCount and lapsDriven fields. I did, didn't I?

GoKart.java 
class GoKart {
  public static final int MAX_BARS = 8;
  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) {
    int newBarCount = barCount -= laps;
    if (newBarCount < 1) {
      throw new IllegalArgumentException("Not enough battery bars!");
    }
    barCount = newBarCount;
    lapsDriven += laps;
  }
}

2 Answers

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher
Jennifer Nordell
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there! Actually no, you change barCount before you throw the exception in this line:

 int newBarCount = barCount -= laps;

Remember that the -= will take barCount minus laps and assign it back into barCount thus changing the value. However, I'd like to give some hints here on how to solve this and we'll see if you can get it from there.

  • There is no need to create a new variable. newBarCount can and should be removed.
  • Check to see if laps is greater than the bar count
  • If it is, throw an exception
  • The rest of the code should remain unchanged.
  • The code you add to this challenge should only contain an if statement with a block containing one line that throws a new IllegalArgumentException

Good luck, but let me know if you're still stuck! :sparkles:

adil rafaa
adil rafaa
3,194 Points
adil rafaa
adil rafaa
3,194 Points

First you don't need to create new variable newBarCount , and then you can just check if ( barCount > = 0) then throw an exception ! good luck