GoKart

Question

Error for get.Message()

Example.java

class Example {

  public static void main(String[] args) {
    GoKart kart = new GoKart("purple");
    if (kart.isBatteryEmpty()) {
      System.out.println("The battery is empty");
    }
      kart.drive(3);
      kart.drive(1);
    while(kart.charge()) {
      System.out.println("Driven On");
    }
    try {
      kart.drive(42);
      System.out.println("Battery Down");
    }catch (IllegalArgumentException iae) {
      System.out.println("Whoa there");
      System.out.printf("The error was %s \n", 
                        iae.getMessage());
    }
  }
}

GoKart.java

class GoKart {
  public static final int MAX_BARS = 8;
  private int barCount;
  private String color;
  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 newLaps = laps - barCount;
    if (newLaps < barCount) {
      throw new IllegalArgumentException("Not enough battery remain");
    }
    newLaps = barCount;
  }

}

Answer 1 · 2017-01-01T17:42:28Z

January 1, 2017 5:42pm

Hey Nirbhay Agarwal!

First of all, in line ten of your first code block, you are trying to get a boolean back but in GoKart.java you defined the method .charge() to give NOTHING back (void). You would either have to change this:

public void charge() {
    barCount = MAX_BARS;
  }

to this:

public boolean charge() {
    barCount = MAX_BARS;
    return false;
  }

But this wouldn't let the program print the message "Drive on" because a while-loop only runs while the condition is true. If .charge() returns FALSE now after having loaded barCount, the while-loop will automatically quit the loop and it will not print "Drive on".

You should put the code above into the if-statement where it is checking whether the battery is empty. Like this:

if (kart.isBatteryEmpty()) {
      System.out.println("The battery is empty");
      kart.charge();
      System.out.println("Driven On");
    }

I think the other problem you had was that you used "<" instead of ">" in this code:

 public void drive(int laps) {
    int newLaps = laps - barCount;

    //RIGHT HERE//
    if (newLaps < barCount) {
      throw new IllegalArgumentException("Not enough battery remain");
    }
    newLaps = barCount;
  }

I hope this helps! Julian

Answer 2 · 2017-01-02T21:21:51Z

January 2, 2017 9:21pm

In this challenge you shouldn't have to alter the GoKart code at all (and I think the challenge ignores any edits to that file anyway). Try restarting from scratch. The only thing you need to do is put a try/catch block around the drive(42).

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