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Java Java Objects Harnessing the Power of Objects Increment and Decrement

Posted by David Gann
David Gann
546 Points

how do I shorthand adding a lap to laps driven? I currently have lapsDriven++ as the shorthand but its not working.

I cant get it to add laps driven using the correct shorthand. Help!

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 () {
    barCount = MAX_BARS;
  }

  public boolean drive () {
    boolean lapsDriven = false;
      if (!isDriven()) {
        barCount--;
        lapsDriven++;
      }  
    return lapsDriven;
  } 

}

1 Answer

Simon Coates
Simon Coates
8,481 Points
Simon Coates
Simon Coates
8,481 Points

Are you shadowing the main field? You seem to have a field and a local variable called lapsDriven and you aren't using the this keyword to access the field. And I think you have two drive methods with the same signature (name and same params). And you're referencing a method called isDriven that doesn't seem to exist. The challenge isn't offering helpful error messages. It accepts:

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 () {
        barCount--;
        lapsDriven++;         
  }
}

If would probably be a good idea to wrap the increment/decrement in if (!isBatteryEmpty()) , but it doesn't seem to care.

David Gann
David Gann
546 Points

Hey thanks for your response. It helped me realize I added that an unnecessary variable to the code. I got it worked out.