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Java Java Objects Harnessing the Power of Objects Throwing Exceptions

Posted by shiny peanut
shiny peanut
5,113 Points

Trouble throwing exceptions

Am I trying to do more than it is asking for? Every time I try to finish this course, I get stuck. I really don't get it and this course is moving too fast for me to fully get each new concept back to back. If you can, please really break this problem down because I do not understand it at all.

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) {
    lapsDriven += laps;
    barCount -= laps;
  }
    int newAmount = barCount + laps;

     if (newAmount < 0) {
      throw new IllegalArgumentException("Not enough bars!");
   }        
    lapsDriven += laps;
    barCount -= laps;  
  }

}

4 Answers

Steven Parker
Steven Parker
229,657 Points
Steven Parker
Steven Parker
229,657 Points

You're actually pretty close! You have a few duplicated lines and a math error:

  public void drive(int laps) {
//  lapsDriven += laps;  <- these lines are copies of the ones below
//  barCount -= laps;    <- I have commented them out here but
//}                      <- they can be deleted
    int newAmount = barCount + laps;  // SUBTRACT the laps
//                  barCount - laps   <- instead of adding them
    if (newAmount < 0) {
      throw new IllegalArgumentException("Not enough bars!");
    }        
    lapsDriven += laps;
    barCount -= laps;  
  }
Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

The code you wrote you should work. It's just outside the closing brace of the drive method so it's considered a syntax error. If you remove the first 3 line lines it should be fine.

shiny peanut
shiny peanut
5,113 Points
shiny peanut
shiny peanut
5,113 Points

I assume by "the first three lines," you mean lapsDriven += laps; barCount -= laps; and int newAmount = barCount + laps;? I removed them and it still doesn't work and I still don't get what is happening with the code regardless.

shiny peanut
shiny peanut
5,113 Points
shiny peanut
shiny peanut
5,113 Points

Thank you! That was super helpful