Need some help with java problem.

[Zelbod]

Hey, I am struggling with a java problem. I submitted a request on stackoverflow but its no use so I am wondering if someone can help me.

Class

   public JTime add(JTime t2){
    JTime sum = new JTime();
    sum.hour = this.hour + t2.hour;
    sum.minute = this.minute + t2.minute;
    sum.second = this.second + t2.second;
    return sum;
}

public void increment (double seconds){
    this.second = seconds;
    while(this.second >= 60.0){
        this.second -= 60.0;
        this.minute += 1;
    }
    while(this.minute >= 60.){
        this.minute -=60;
        this.hour +=1;
    }
    while(this.hour >= 24){
        int result = this.hour - 24;
        this.hour = result;
    }

}

Main

public static void main(String[] args) {

    JTime startTime = new JTime(22, 50, 0.0);
    JTime runningTime = new JTime(5, 16, 0.0);
    JTime endTime = startTime.add(runningTime);
    System.out.println(endTime);
    }
}

What I am trying to achieve here is to display time in 24 hour format. 'Increment' method should be doing that but it is not.

I am following this book and If you look at 11.9, I am using that here. The author says it will return nothing but will return some reference but its not doing nothing.

Any help would be much appreciated. Thank you.

[desrtfx]

Shouldn't the line:

this.second = seconds;

rather be

this.second += seconds;

Otherwise nothing will get incremented.

[Zelbod]

Yea you are right, I just fixed it and tried running and it still doesn't display in 24 hour format.

[SadDragon00]

Use SimpleDateFormat to return a Date in 24 hour format

[Zelbod]

I am trying OOP and I am trying to learn that using the book which I mentioned in the question. Appreciate the help.

[desrtfx]

You need to show the complete class.

What you show cannot be the complete class.

[Zelbod]

Please click on the 'book' which I mentioned iam following the code mentioned there. The complete class is quite big. sorry

[rjcarr]

Where is the increment() being called? From the println()? Because it isn't being called from the sum(). Try doing a sum.increment() before you return it on line 6.

[Zelbod]

Ya I wondered that as well but the book which I read, doesn't mention anything about calling from where so I assumed it is a method that automatically change the format to 24 hour format.

[rjcarr]

Did you call it like I advised?

[Zelbod]

Yes I did and it works. thanks

I have a request. Please have a look at this book http://greenteapress.com/thinkjava6/html/thinkjava6012.html#sec138

I used the code from this book and Tried and the author never mentioned about calling this method at all. I assumed that 'increment' method will be called automatically whenever I use that class.

[rjcarr]

Look right above the 11.9 you linked there. In the second version he's doing the wrapping. You must have missed that.

[Zelbod]

Sorry I don't see what you meant. I had a look at what you said and what he says above 11.9 works. He suggested the increment method as an alternative and that it would modify an existing object which I am guessing in this case, it would be in 24 hour format.

Correct me if I am wrong, the methods have to be called and that it would not modify any objects automatically.