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

Posted by Paul Joiner
Paul Joiner
1,682 Points

compiler error ("Preview won't load") What am I doing wrong? [Incrementing]

I'm trying to follow this using the same logic provided in the example video, but I can't get this code to compile. Even worse, the preview function won't load to tell me where my error are. Can anyone please help me?

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 boolean charge() {
    boolean isCharging true;
    if (!isFullyCharged()) {
      mBarsCount++;
      isCharging = true;
    }
    return isCharging;
  }

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

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

}

4 Answers

Kourosh Raeen
Kourosh Raeen
23,733 Points

The charge method has a return type of void but you've changed it to boolean. Change it back to void and remove the return statement. Also, instead of the if statement you need to use a while loop. Loop until the batter is charged and inside the loop increment mBarsCount.

Paul Joiner
Paul Joiner
1,682 Points 
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++;
  }



}
'''
I'm still getting a compiler error. Am I putting the while loop in the wrong place?
Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

You have put the code in the wrong method. It should be in the charge() method, not in the isFullyCharged() method.

Paul Joiner
Paul Joiner
1,682 Points
Paul Joiner
Paul Joiner
1,682 Points 
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;
    while(!isFullyCharged()) {
      mBarsCount++;
  }

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

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

}

I've moved the while loop to the charge() method, but the code still won't compile. Is the mBarsCount=MAX_ENERGY_BARS line throwing me off? Or perhaps the fact that I'm using the isFullyCharged method? Thanks again for the help!

Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

Remove the line mBarsCount = MAX_ENERGY_BARS; Also, the while loop is missing a closing }

Paul Joiner
Paul Joiner
1,682 Points

It worked. Thank you!