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Java Java Objects (Retired) Harnessing the Power of Objects Incrementing

Posted by Pierce Mulligan
Pierce Mulligan
1,106 Points

Can't solve my compiler error.

Where is my code failing?

GoKart.java 
public class GoKart {
  public static final int MAX_ENERGY_BARS = 8;
  private String mColor;
  private int mBarsCount;

  public GoKart(String color) {
    mColor = color;
    mBarsCount = 0;
  }

  public String getColor() {
    return mColor;
  }

  public void charge() {
    mBarsCount = MAX_ENERGY_BARS;
  }

  public boolean isBatteryEmpty() {
    return mBarsCount == 0;
  }

  public boolean isFullyCharged() {
    return mBarsCount == MAX_ENERGY_BARS;
  } while(!isFullyCharged()) {
     mBarsCount = MAX_ENERGY_BARS;
  }

}
Pierce Mulligan
Pierce Mulligan
1,106 Points

I am trying to use a while loop to charge the kart when it is not fully charged "!isFullyCharged".

3 Answers

andi mitre
STAFF
andi mitre
Treehouse Guest Teacher
andi mitre
andi mitre
Treehouse Guest Teacher

Hey Pierce,

So your syntax error is that you have a while loop after closing the isFullyCharged() method.

However, the exercise is to change the charge() method by utilizing the isFullyCharged() mehtod.

public class GoKart {
  public static final int MAX_ENERGY_BARS = 8;
  private String mColor;
  private int mBarsCount;

  public GoKart(String color) {
    mColor = color;
    mBarsCount = 0;
  }

  public String getColor() {
    return mColor;
  }

  public void charge() {
    while(!isFullyCharged()){
      mBarsCount++;
    }

  }

  public boolean isBatteryEmpty() {
    return mBarsCount == 0;
  }

  public boolean isFullyCharged() {
    return mBarsCount == MAX_ENERGY_BARS;
  }

}

So you use the while loop with the ! to check when the gokart is not fully charged and in that case you want to charge the gokart so you increment the mBarsCount variable.

Hope that helps!

Cheers

Pierce Mulligan
Pierce Mulligan
1,106 Points

That makes sense, but now I am experiencing a compiler error, but when I click preview there's no text saying where or what the error is.

andi mitre
andi mitre
Treehouse Guest Teacher
andi mitre
andi mitre
Treehouse Guest Teacher

If you copy and delete the code it should pass. At least, it passed for me.

Thanks @piercemulligan

Pierce Mulligan
Pierce Mulligan
1,106 Points

I got it working on my own, thanks again.

Hayes McCardell II
Hayes McCardell II
643 Points
Hayes McCardell II
Hayes McCardell II
643 Points 
  public boolean isFullyCharged() {
    return mBarsCount == MAX_ENERGY_BARS;
  } while(!isFullyCharged()) {
     mBarsCount = MAX_ENERGY_BARS;
  }

The problem is that you are returning a value and then closing the function with a curly brace, and then adding the while loop outside of a function.

The instructions ask for the while loop using the !isFullyCharged, which looks good. But it needs to be inside the function block. The instructions also ask for the mBars to be incremented (added to) during each run through the while loop.

You can increment a value by adding something to it. Such as: 

while(!full){
gas = gas + 1;
}

or 

while(!full){
++gas;
}

Hopefully this helps you along the way without giving you the code ;)

Hayes McCardell II
Hayes McCardell II
643 Points
Hayes McCardell II
Hayes McCardell II
643 Points

Also, a return stops the code right away and exits the current code block.

Any remaining code in that function will not be executed. So make sure you do operations before you return a value.

That being said, a function can return more than one value if there is decision logic.

if (customerTall){
return large;
}

if(customerShort){
return small;
}