Ulf Dittmer wrote:
Lu Kim Hui wrote:i add sum = 0 after line 50
That's the wrong place. You need to do that after a summation is done, not right in the middle of it.
Ulf Dittmer wrote:You need to reset "sum" to zero whenever you have output the result of a summation.
Campbell Ritchie wrote:Paper
There are two sorts of paper when I am around.Type A paper: this is white and is a hazard to life and limb because I try to write on it and nobody can read it. Type B paper: this is not all white, but has writing on already, and is a hazard to life and limb because the chances of my losing it are in proportion to the importance of the writing.
In my opinion, you should instantiate that List inside the constructorYou should also avoid if (...) b = true ; else b = false; Look here for a better example.
Are you closing a Scanner using System.in? You shouldn’t do that. To find out why, add this line after line 20
Winston Gutkowski wrote:Another tip for you: Get used to reading your stacktraces thoroughly.
Go through them and work out exactly which statements are involved and the order they were invoked. Personally, I use a yellow marker pen; but I'm an old fart and I hate looking at large programs on screens (and I recycle my paper ).
Winston
Winston Gutkowski wrote:
Lu Kim Hui wrote:THANKS ALOT!!!
Another satisfied customer. And isn't it much better when you work it out for yourself?
Winston
fred rosenberger wrote:This line:
private ArrayList<Integer> salesList;
says "Eventually, I will create an AraryList that can hold Integers, and I will refer to it by the name salesList".
That's like saying "Someday, i will have a dog and call him 'Rover'". That doesn't mean you HAVE a dog - it just means that someday you will, and you've already picked out the name.
You never create the ArrayList. So, when you further down say "add something into the ArrayList named 'salesList'", the JVM is saying "ummm....WHAT arraylist? There is no such thing!!!"
Winston Gutkowski wrote:
Lu Kim Hui wrote:Erm... because this is an exercise given from my lecturer, and the requirement is reading from the file and store inside an INTEGER arraylist and lastly print them out ^^"
No. That's the what. You're trying to find out why you're getting an NPE. Have a look at my last question again.
Winston
Campbell Ritchie wrote:Yes, that is what he means. Enter the following line before line 35 and after line 34: