Programming C# 4.0, 6th Edition

Chapter 7. Arrays and Lists

Most programs have to deal with multiple pieces of information. Payroll systems need to calculate the salary of every employee in a company; a space battle game has to track the position of all the ships and missiles; a social networking website needs to be able to show all of the user’s acquaintances. Dealing with large numbers of items is a task at which computers excel, so it’s no surprise that C# has a range of features dedicated to working with collections of information.

Sets of information crop up so often that we’ve already seen some of what C# has to offer here. So we’ll start with a more detailed look at the collection-based features we’ve already seen, and in the next chapter we’ll look at the powerful LINQ (Language Integrated Query) feature that C# offers for finding and processing information in potentially large sets of information.

Arrays

The ability to work with collections is so important that the .NET Framework’s type system has a feature just for this purpose: the array. This is a special kind of object that can hold multiple items, without needing to declare a field for each individual item. Example 7-1 creates an array of strings, with one entry for each event coming up in one of the authors’ calendars over the next few days. You may notice a theme here (although one misfit appears to be a refugee from an earlier chapter’s theme, but that’s just how the author’s weekend panned out; real data is never tidy).

Example 7-1. An array of strings ...