The NSRange type is used to specify ranges of locations, typically items in an array, characters in a string, and bytes in a data object.

As 'boundary' or 'fencepost' errors are a particularly common problem in programming, it is important that you understand how an NSRange works.

An NSRange consists of a location and a length. The points that are considered to lie in a range are the integers from the location to the location plus the length, so the number of points in a range is the length of the range plus one.
However, if you consider these points like the marks on a ruler, you can only store information between points. So the number of items that can be stored in a range is the length of the range.