Iteration over array using its count continues for an extra step

Question

I have these arrays set up to go into a NSDictionary and then they are added to an NSMutableArray. This is to set up sections.

NOTE: The content of the arrays are a bit random as I am just trying something out.

Now the bit I was expecting is that the word "Awesome!!" would only be re-iterated 3 x 3 times as the counts of both the NSMutableArray and headArray are only 3.

So why is it re-iterated 4 x 3 times when I use the <= operator sign? Should this not be done 3 times as it is matching the count to be only 3 times?

Now I appreciate that the section count is set to 0 which could be an explanation, but it needs to be 0 to be at the top of the UITableView.

listOfItems = [[NSMutableArray alloc] init];
headerArray = [[NSArray alloc] initWithObjects:@"Country 1", @"Country 2", @"Country 3", nil];

NSArray *countriesToLiveInArray = [NSArray arrayWithObjects:@"Iceland", @"Greenland", @"Switzerland", @"Norway", @"New Zealand", @"Greece", @"Italy", @"Ireland", nil];
NSDictionary *countriesToLiveInDict = [NSDictionary dictionaryWithObject:countriesToLiveInArray forKey:@"Countries"];

NSArray *countriesLivedInArray = [NSArray arrayWithObjects:@"India", @"U.S.A", nil];
NSDictionary *countriesLivedInDict = [NSDictionary dictionaryWithObject:countriesLivedInArray forKey:@"Countries"];

NSArray *thirdArray = [NSArray arrayWithObjects:@"Row 01", @"Row 02", @"Row 03", @"Row 04", nil];
NSDictionary *thirdDictionary = [NSDictionary dictionaryWithObject:thirdArray forKey:@"Countries"];

---

if (headerArray.count == listOfItems.count)
{
    for (section = 0; section <= listOfItems.count; section++)
    {
        NSLog(@"AWESOME!!");
    }
}

---

2013-02-17 20:10:06.323 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.324 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.325 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.326 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.327 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.328 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.330 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.331 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.332 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.332 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.334 TableView[3667:11303] AWESOME!!
2013-02-17 20:10:06.335 TableView[3667:11303] AWESOME!!

Answer 1

No. What you're doing would be appropriate for 1-indexed arrays. NSArray, however, is 0-indexed. What happens in your for loop is that section goes from 0 to listOfItems.count, that is from 0 to 3, which means 4 iterations (one for 0, 1, 2, and 3, respectively). Use the < operator instead.

See the Wikipedia article on half-open intervals and zero-based numbering.