Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Java Objects Harnessing the Power of Objects Overload Methods

Kendhall Lebron Ruiz
PLUS
Kendhall Lebron Ruiz
Courses Plus Student 1,143 Points
Posted by Kendhall Lebron Ruiz
Kendhall Lebron Ruiz
Courses Plus Student 1,143 Points

I don't understand the drive method

It's asking "Modify the drive method to define a parameter of how many laps should be driven. Update the method body to handle the new parameter." I know I have to use the += and -= thing but I don't know how to use them here. I already got the right answer but I guessed it. An explanation would be appreciated.

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

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

You say that you "got the right answer", but it's not shown here. This is the code the challenge starts with.

But to explain the "+= and -= thing", those are the increment and decrement operators. Both of them change the value of the term on the left by the amount represented on the right. So "dogs += 3" would raise the count of "dogs" by 3, and "students -= seniors" would decrease the current student count by the number of folks who are graduating (the senior class).