Welcome to the Treehouse Community
Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.
Looking to learn something new?
Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.
Start your free trialTinashe Nyaruwanga
525 PointsThrowing illegalArgumentException - Not enough battery
Here's my code - I thought I nailed it but I obviously did something wrong what is it?
public class GoKart { public static final int MAX_BARS = 8; private String mColor; private int mBarsCount;
public GoKart(String color) { mColor = color; mBarsCount = 0; }
public String getColor() { return mColor; }
public void drive() {
try{
drive(1);
} catch (illegalArgumentException iae) {System.out.println("Not enough battery remains");
}
public void drive(int laps) { // Other driving code omitted for clarity purposes int newBarsCount = mBarsCount -= laps; if (newBarsCount < mBarsCount) { throw new illegalArgumentException("Not enough battery remains");
}
}
public void charge() { while (!isFullyCharged()) { mBarsCount++; } }
public boolean isBatteryEmpty() { return mBarsCount == 0; }
public boolean isFullyCharged() { return mBarsCount == MAX_BARS; }
}
public class GoKart {
public static final int MAX_BARS = 8;
private String mColor;
private int mBarsCount;
public GoKart(String color) {
mColor = color;
mBarsCount = 0;
}
public String getColor() {
return mColor;
}
public void drive() {
try{
drive(1);
} catch (illegalArgumentException iae) {System.out.println("Not enough battery remains");
}
public void drive(int laps) {
// Other driving code omitted for clarity purposes
int newBarsCount = mBarsCount -= laps;
if (newBarsCount < mBarsCount) {
throw new illegalArgumentException("Not enough battery remains");
}
}
public void charge() {
while (!isFullyCharged()) {
mBarsCount++;
}
}
public boolean isBatteryEmpty() {
return mBarsCount == 0;
}
public boolean isFullyCharged() {
return mBarsCount == MAX_BARS;
}
}
4 Answers
Craig Dennis
Treehouse TeacherHi Tinashe!
You are super close! Remember you want to not modify the mBarsCount
before using it. You might've accidentally did it, but you have mBarsCount -= laps
. See how you have the -=? Try just minus.
Hope it helps!
Tinashe Nyaruwanga
525 PointsOkay, I have removed my the equal sign and my code reads
public void drive(int laps) {
int newBarsCount = mBarsCount - laps;
if (newBarsCount < mBarsCount) {
throw new illegalArgumentException("Not enough battery remains");
}
}
its still not working? Am I missing something?
Craig Dennis
Treehouse TeacherSo you want the exception to happen if the newBarsCount
would be less than zero. And then you want to set the mBarsCount
to the result stored in newBarsCount
, so that you update the battery properly.
Jess Sanders
12,086 Points public void drive(int laps) {
if (laps > mBarsCount) {
throw new IllegalArgumentException("Not enough battery remains");
}
// Other driving code omitted for clarity purposes
mBarsCount -= laps;
}
You don't need the newBarsCount at all, really.
ISAIAH S
1,409 PointsISAIAH S
1,409 PointsHi Craig, I've completed the challenge with
mBarsCount -= laps;
.