How to specify and use arrays in .h and .m files?

Question

Ok, this is pretty basic. For regular variables, no problem.
(in .h)
@interface Mine : NSObject {
int x;
@property (assign) int x;
@end
(in .m)
@implementation Mine
@synthesize x;
@end
But, when I want to specify an array of objects, it fails, with "error: bad property declaration".
(in .h)
@interface Mine : NSObject {
int x[15][10];
@property (assign) int x[15][10];
@end
(in .m)
@implementation Mine
@synthesize x;
@end
If I don't use @property and @synthesize, I can use these arrays just fine in the .m file.
However, the problem I run into, quite often is that I cannot use these without a warning, which usually causes an exception:
x[myX][myY] = s;
or
[obj getX:myX :myY];
gives a warning "assignment from a distinct Objective-C type" or "obj may not respond to -getX" which usually ends up with an exception:
2009-08-17 16:56:00.512 AppName[9638:20b] * -[Mine getX::]: unrecognized selector sent to instance 0x103a800
2009-08-17 16:56:00.538 AppName[9638:20b] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[Mine getX::]: unrecognized selector sent to instance 0x103a800'
2009-08-17 16:56:00.548 AppName[9638:20b] Stack: (
807902715,
2426465851,
808284155,
Can someone tell me how to do this properly?
My app wants to create 2 arrays of 15x9 to manage a playing board on an x,y grid.
I want one array to be of type NSString, and the other to be of class Piece (one of my own classes). In some places it works without the @property declaration using a custom getter and setter, but in other places the exact same code gives me one of the errors above.
What am I missing?

Answer 1

Still working this out. In my App, I really only use the "NSMutableArray* cells" to use as a representation of my initial layout, built from a string obtained in my scene plist file. (sceneTableau)
An example board can be seen at http://reststop.homeip.net/dev/Picture4.png for those interested in seeing what the working code does.
- (Board*) setupBoard:(Board*)b {
if (b) {
int loc=0;
b.cells = [[NSMutableArray alloc] initWithCapacity:(boardWidth*boardHeight)];
for (int n=0; n<boardHeight; n++) {
for (int m=0; m<boardWidth; m++) {
NSRange myRange=NSMakeRange(loc*3,2); // get first 2 of 3 chars
NSString* t = [b.sceneTableau substringWithRange:myRange];
[b.cells insertObject:t atIndex:loc];
[t release];
loc++; // increment to next piece
} // for m
} // for n
}This works great, doing my own math for x,y. In fact this initialization loop ONLY used m,n for documentation and could simply be "for (int loc=0; loc<boardWidth*boardHeight; loc++)" to shorten the code. Since I don't ever actually modify the NSString*s I could make the setter routine for cells be an empty void method, e.g. "- (void) setCells:(NSString*) {}".
I also noticed a couple of method in the NSString.h file:- (NSArray *)componentsSeparatedByString:(NSString *)separator;
- (NSArray *)componentsSeparatedByCharactersInSet:(NSCharacterSet *)separator;which would allow me to simply use:b.cells = [b.sceneTableau componentsSeparatedByCharactersInSet:whitespaceAndNewlineCharacterSet];since my sceneTableau string is simply 135 sets of 2-character codes separated by a space or a newline.
Taking this in the other direction, I could dispense with the cells array and simply use the sceneTableau field and my getter routine would be:- (NSString*) getCells:(int)loc {
NSRange myRange=NSMakeRange(loc*3,2);
return [b.sceneTableau substringWithRange:myRange];
} (I may go ahead and make this change as it is a little more compact and I don't use this array except to initialize the display).
However, for the pieces, I do need to keep an array, as there is more structure to the objects, and some objects will move from one position to another and the display will need to be redrawn after each move, changing the appearance of at least 2 positions and as many as 4 positions.
If I did need to modify the contents of a cell, then I presume that I should really use objects of type NSMutableString* instead of NSString, and then the proper way to set a new value would be:
- (void) setCells:(NSString* s) {
NSMutableString* c = [self.cells objectAtIndex:(x+y*boardWidth)];
[c setString:s];
I am not sure what I need to do in the way of releasing c in this context. Does c go away at the end of the invocation, and no longer points to anything, or do I need to assign nil, or release c?
I presume I could also do as my current code does[self.cells replaceObjectAtIndex:(myX+myY*boardWidth) withObject:s];but again I am not sure what I need to do about release. I gather that the NSArray handles retaining and releasing the objects which are put into or removed from its instance, and they will all be released when I release the NSArray in my dealloc method.
Based on this, I do need to rethink my NSMutableArray* of pieces, as I will need to write methods that move the pieces and my earlier model does not allow them to move freely without having to perform some coding gymnastics in Objective-C. I will still need to use an array, NSMutableArray most likely.
Have I missed anything?
A quick question on my "setupBoard" routine above. You may have noticed that it takes a Board* and returns a Board*. I currently have to use[b setupBoard:b]; which seems wrong, but it works. What is the proper way to define and invoke this message so that my code would look more like this???[b setupBoard];
and then to finish and do my releases
[b upsetBoard];Is it correct Objectivc-C syntax to have a method that manipulates the contents of an object, such as my setupBoard method, and to say:invocation:
[boardPointer setupBoard];
implementation:
- (void) setupBoard {
if ( self ) { // test for non-nil
[self.cells = [self.sceneTableau componentsSeparatedByCharactersInSet:whitespaceAndNewlineCharacterSet];