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Java

Posted by Larissa Röhrig
Larissa Röhrig
1,787 Points

Java Incrementing GoKart Challenge; Missing return challenge, need help...

I need help with my GoKart challenge because I get the error message "missing return statement { “ I'm not really sure what to change ....

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() {
    boolean isFullyCharged= false;
    while(!this.isFullyCharged()) {
      mBarsCount++;
      return mBarsCount == MAX_ENERGY_BARS;
  }
  }

}

Error message Missing return statement { line 29

3 Answers

Gabriel Melo
Gabriel Melo
3,808 Points

You just have add the while loop to the charge method. Like this:

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;
  }

}

Let me know if it works for you!

Adam Sawicki
Adam Sawicki
15,967 Points
Adam Sawicki
Adam Sawicki
15,967 Points

You should write it like this:

public boolean isFullyCharged() {
    boolean isFullyCharged= false;
    while(!this.isFullyCharged()) {
      mBarsCount++;
    }
return mBarsCount == MAX_ENERGY_BARS;
}

In your soultion you will always recieve the same result because after incrementing mBarsCount you always break the while loop with return statement. Second thing is that It is possibility that the program won't enter the loop and then there would be no return statement at the end of the method.

Regards

Larissa Röhrig
Larissa Röhrig
1,787 Points

So I just tried it the way you suggested but it still isn't working ....

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() {
    boolean isFullyCharged= false;
    while(!this.isFullyCharged()) {
      mBarsCount++;
    }
    return mBarsCount == MAX_ENERGY_BARS;
  }
}

what am I doing wrong ?

Adam Sawicki
Adam Sawicki
15,967 Points
Adam Sawicki
Adam Sawicki
15,967 Points

Try this. I've change methods charge() and isFullyCharged().

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(!this.isFullyCharged()) {
      mBarsCount++;
    }
  }

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

  public boolean isFullyCharged() {
    if(mBarsCount < MAX_ENERGY_BARS){
      return false;
    } else {
      return true;
    }
  }
}
Larissa Röhrig
Larissa Röhrig
1,787 Points

Thanks now it's working :)