Programming in Objective-C

15. Numbers, Strings, and Collections

This chapter describes how to work with some of the basic objects provided in the Foundation framework. These include numbers; strings; and collections, which refers to the capability to work with groups of objects in the form of arrays, dictionaries, and sets.

The Foundation framework contains a plethora of classes, methods, and functions for you to use. Approximately 100 header files are available on the Mac, and 70 are available as part of GNUStep that you can import into your program. As a convenience, you can simply use the following import:

#import <Foundation/Foundation.h>

Then you don't have to worry about whether you are importing the correct header file. This header file is automatically imported ...