Question

I am working on a game and in my init method it gives EXC_BAD_ACCESS when I do [self loadGravityCenters]. Here is the definition of that method:

-(void) loadGravityCenters {

    //These P1, P2, etc. are for seeing where the EXC_BAD_ACCESS is in the method.
    printf("P1\n");
    //Get and open the file with coordinates
    NSString *filePath =  [[NSBundle mainBundle] pathForResource: @"gravitycenter" ofType: @"ballpoint"];
    FILE *fileHandle = fopen([filePath cStringUsingEncoding:NSASCIIStringEncoding],"r");
    //First array for storing the coordinates from the file.
    NSMutableArray *coord;
    //Vanilla C doesn't have an NSMutableArray, use tempCoord to place it in the NSMutableArray.
    int tempCoord;
    //i is used to keep track of where to assign stuff in coord).
    int i = 0;
    while (!feof(fileHandle)) { //Read file.
        //Next check point.
        printf("P2\n");
        //Assign tempCoord a number from file.
        fscanf(fileHandle, "%d", &tempCoord);
        //Convert the integer to NSNumber (so I can put it in coord.
        NSNumber *intToNSNumber = [NSNumber numberWithInt:tempCoord];
        [coord insertObject:intToNSNumber atIndex:i];
        i++;
    }
    for (int j = 0; j < [coord count]; j+=2) { //Make the coord array into an array of CGPoints
        printf("P3\n"); //Check point.
        //Assign a gravityCenters (declared in header) a series of points.
        [gravityCenters addObject:[NSValue valueWithCGPoint:CGPointMake([[coord objectAtIndex:j] floatValue], [[coord objectAtIndex:j+1] floatValue])]];
    }

    for (int j = 0; j < [gravityCenters count]; j++) {
        printf("P4\n"); //Last checkpoint.
        //gravityWells (declared in header) is used to store CCSprites, make a bunch of sprites with the positions stored in gravityCenters.
        [gravityWells addObject:[CCSprite spriteWithFile:@"GravityCenter.png"]];
        [[gravityWells objectAtIndex:j] setPosition:[[gravityCenters objectAtIndex:j] CGPointValue]];
        printf("gravityWell=%f,%f\n", ((CCSprite *)[gravityWells objectAtIndex:j]).position.x, ((CCSprite *)[gravityWells objectAtIndex:j]).position.y);
        [self addChild:[gravityWells objectAtIndex:j]];
    }
}

To summarize:

Make an array of intgers that stores coordinates. Convert it so it can be placed in an array of CGPoints. Make a bunch of CCSprites and give them the coordinates from the array filled with CGPoints.

The file I am using looks like this:

70 100
80 89
46 545

The program fails at checkpoint P3. I’ve tried replacing the line:

    for (int j = 0; j < [gravityCenters count]; j++) {

With:

    for (int j = 0; j < [coord count]-2; j+=2) {
    //And:
    for (int j = 0; j < [coord count]-3; j+=2) {

Wondering it is only an out-of-bounds thing. But doing what I did above doesn’t seem to change anything. Any help would be greatly appreciated.

Answer 1

You need to allocate the array first before you can use it. Try:

NSMutableArray *coord = [[NSMutableArray alloc] init];

Hope that helps!