Hi Sina, Your point is taken. I confess it's not the biggest thing I'm worrying about right now, but if you could point me towards any primers on elements of style for OOP or have any individual tips you feel would be appropriate, I'll certainly take a look at them and try and modify my coding practices accordingly. I am, as of now, exclusively a speech user when programming, and I bet there's plenty of things like this I do "incorrectly" as a byproduct of the speech medium.
Best, JW Sina Bahram wrote:
He does ... they are of type room. Why room is not capitilized , since it is a class, I think is a further major big deal ; however. Take care, Sina -----Original Message----- From: programmingblind-bounce@xxxxxxxxxxxxx [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Michael Malver Sent: Tuesday, March 11, 2008 6:19 PM To: programmingblind@xxxxxxxxxxxxx Subject: RE: (Java) Dealing With a Rogue Null Pointer Exception at Runtime Look up the proper declaration for arrays. I think you have to explicitly state the object type that is going to go in each element. I haven't had to declare an array in quite some time, so I may be wrong about this. -----Original Message----- From: programmingblind-bounce@xxxxxxxxxxxxx [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Jared Wright Sent: Tuesday, March 11, 2008 3:20 AM To: programmingblind@xxxxxxxxxxxxx Subject: (Java) Dealing With a Rogue Null Pointer Exception at Runtime Hi all, The following constructor keeps giving me a null pointer exception if called at runtime. I guess the easiest place to start is with a code exerpt. The context is that this class, cave, is made up of an array of rooms. Each room has a number, three adjacent rooms, a description, etc. It also tracks what the current room is, per the user's direction in the larger scope of the program. The constructor gets its info from a text file, and the amount of rooms in the cave could vary based on this text file's contents. I think it is this flexible length of the array of rooms for each cave object that's the trouble spot, but beyond that I am admittedly stuck. Note that TextReader serves much as the Scanner class would, this one just has a couple of extra quirks that I like, thus I'm using it instead. public class cave { private int current; private int numrooms; // Variables for the current room the user is in and the number of rooms in the cave. private room myroom[]; // The array of room objects for the cave. public cave(String filename) throws IOException { current = 1; TextReader file = new TextReader(new FileInputStream(filename)); // numrooms=file.readInt(); // Reads in the first integer of the file, which is the number of rooms the cave must hold. myroom = new room[numrooms-1]; // Attempt to populate the myroom array with the appropriate number of rooms. This is the line the exception actually references, along with the line that called the constructor (from another file). } The constructor actually goes on to fill the room objects with more specific data (room number, description, etc.). Is there a better way to go about this? Will I have to somehow explicitly define the array length, or is there a way that the constructor can make the array the appropriate size based on the data in the file? Might I be looking in the wrong place for the source of this error?More code available on request. I didn't want the snipet to get too big. I hope I've made things clear, and thanks for any guidance, everyone.Jared __________ View the list's information and change your settings at //www.freelists.org/list/programmingblind __________View the list's information and change your settings at //www.freelists.org/list/programmingblind__________View the list's information and change your settings at //www.freelists.org/list/programmingblind
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