error index beyond bounds - cocos2d-iphone

Question

-(id) init
{
if( (self=[super init])) {
_targets = [[NSMutableArray alloc] init];
temp = [NSArray arrayWithObjects:#"1", #"2", #"3", #"4",nil];
tempArray = [[NSMutableArray alloc] initWithArray:temp];
resultArray = [[NSMutableArray alloc] init];
[self thelogic];
}
return self;
}
-(void)thelogic
{
int i;
int count = 4;
for (i = 0; i < 3; i ++) {
int index = arc4random() % (count - i);
[resultArray addObject:[tempArray objectAtIndex:index]];
CCSprite *target = [CCSprite spriteWithFile:[NSString stringWithFormat:#"%#.png", [tempArray objectAtIndex:index]]];
target.tag = [[NSString stringWithFormat:#"%#",[tempArray objectAtIndex:index]] integerValue];
[self addChild:target];
[_targets addObject:target];
[tempArray removeObjectAtIndex:index];
}
}
-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
[_targets removeAllObjects];
[self thelogic];
}
from the up code, I get three different numbers and they make three sprites with different image when enter this scene, and I want to touch the screen, the three old sprites will be removed, and three new sprites will show, but the up code always crashes, so how should I fix it? thanks

Answer 1

It is hard to understand what you are trying to do in your theLogic method, but I would suggest you to replace
int index = arc4random() % (count - i);
with
int index = arc4random() % [tempArray count];
This will fix the crash, but I doubt that your program will work as expected. Indeed, you only populate tempArray in the init method; the first call to theLogic will remove all of its elements, and as far as I see the array is not populated anymore. So, when you make ccTouchesBegan be called and then theLogic, tempArray will be empty.
Sorry if I am missing any points.