Question

One thing I’m concerned about is I create two ints, but don’t release them. Would it be better to make them NSIntegers?

-(void) flipCoin {

    int heads = [headsLabel.text intValue];
    int tails = [tailsLabel.text intValue];

    if (random() %2 ==1 )
    {
        heads++;
    }
    else {
        tails++;
    }

    headsLabel.text = [NSString stringWithFormat:@"%d", heads] ;
    tailsLabel.text = [NSString stringWithFormat:@"%d", tails];

}

Answer 1

int is what is known as a primitive type. It is not a pointer to an Objective-C object so you cannot release it. You can’t even send a message to it.

NSInteger is also a primitive type in the sense that it is a typedef to a primitive type (long usually). So you can’t release that either.

What do you need to release? You need to release any object you obtained by sending new, alloc or a method containing copy. You also need to release objects to which you have sent retain. So all of the local variables in the following must be released:

-(void) foo
{
    NSString* aString  = [[NSString alloc] init];
    NSString* aString2 = [aString copy];
    NSString* aString3 = [someOtherString retain];
    NSString* aString4 = [@"some string" copy];
}

NB due to implementation details, you would actually get away with not releasing the aString4 but you don’t need to worry about it.