Please i am lost with the question after the lesson on Incrementing and Decrementing.

Hi there,

For this part ofthe challenge, you are asked:

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.

So, we want to amend the exiting charge method. At the moment, this method just sets mBarsCount to be MAX_ENERGY_BARS. The clue to what the new method should do is given as: Let's use the ! symbol and a while loop. Inside the loop increment mBarsCount. So now we know why the idea is behind the amendment. We want to increment mBarsCount while the helper method, isFullyCharged() is reporting that that battery is not fully charged.

Let's consider the contents of the while loop. The clue says to increment mBarsCount, so let's start with that:

while (//something){
  mBarsCount++;
}

So far, so good! But what are we testing inside the loop condition? We want to know if the battery is NOT full. But we only have one helper method. That tells us when the battery is full - we want the opposite, right? That means we can negate the output of the isFullyCharged() method using the ! operator. We just need to insert that test into the while loop:

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

I hope that helps,

Steve.