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

Posted by Damir Demirovic
Damir Demirovic
Courses Plus Student 446 Points

This is confusing, help please.

Okay, so let's use our new isFullyCharged helper method to change our implementation details of the charge method. Let's make it so it will only charge until the battery reports being fully charged. Let's use the ! symbol and a while loop. Inside the loop increment mBarsCount.

i already incremented mBarsCount but it gives error for some reason, why?

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() {
    while (mBarsCount != MAX_ENERGY_BARS)
      mBarsCount++;
  }

  }

}
tobiaskrause
tobiaskrause
9,160 Points

Please post the error message... "it gives error for some reason" is not rly helpfull.

I think that you need a return statement to return mBarsCount

Mark Miller
Mark Miller
45,831 Points
Mark Miller
Mark Miller
45,831 Points

The isFullyCharged should return a Boolean, so just tell it to return the answer to the test mBarsCount == MAX_ENERGY_BARS. Then use that method plus the while loop inside of the charge method. The instructions say to change the charge method so that it has the conditional happening with the charge. Your while loop can say while (!isFullyCharged()) inside of the charge method.

2 Answers

tobiaskrause
tobiaskrause
9,160 Points
tobiaskrause
tobiaskrause
9,160 Points 
public class GoKart {
  public static final int MAX_ENERGY_BARS = 8;
  private String mColor;
  private int mBarsCount;

  public GoKart(String color) {
    mColor = color;
//sets it to 0
    mBarsCount = 0;
  }

  public String getColor() {
    return mColor;
  }

  public void charge() {
    while(!isFullyCharged())
    {
// adds +1 to mBarsCount so that the while-Loop will stop
      mBarsCount++;
    }
  }

  public boolean isBatteryEmpty() {
    return mBarsCount == 0;
  }
// Is wrong in the beginning since it gets set to 0
  public boolean isFullyCharged() {
// mBarsCount is 0 and gets +1 since charge() adds +1 to mBarsCount as long
// as this method returns false
    return mBarsCount == MAX_ENERGY_BARS;
  }

}
Damir Demirovic
PLUS
Damir Demirovic
Courses Plus Student 446 Points
Damir Demirovic
Damir Demirovic
Courses Plus Student 446 Points

This is error Tobias Krause

./GoKart.java:31: error: class, interface, or enum expected } ^ ./GoKart.java:26: error: incompatible types: int cannot be converted to boolean return mBarsCount; ^ 2 errors