Strings and Container Classes
In this chapter I discuss some of the most common classes available in the Foundation framework. In particular, I discuss the NSString class, used to manipulate all character sequences in Objective-C. NSString offers a convenient interface to create strings, retrieve part of a string, compare string values, and convert them into other formats.
Another important class in the Foundation framework is NSNumber. Numbers are one of the most basic concepts in computer programming, and they are usually handled by the C language as native data types. However, there are times when a number needs to be passed to or stored by other objects. When that is necessary, a wrapper class such as NSNumber is the best way ...