2.1 What's in a Program?

A program consists of English-language instructions called source code. The syntax for these instructions is strictly defined by the language. Source code consists of a series of statements. A statement is an instruction to the complier. Each instruction must be formed correctly, and one task you'll face when learning C# will be to learn the correct syntax of the language. For example, in C# every statement ends with a semi-colon.

Each instruction has a semantic meaning that expresses what you are trying to accomplish. Although you must follow the syntax, the semantics of the language are far more important in developing effective object-oriented programs. This book will provide insight into both the syntax and the semantics of good C# programs.

Save the source code you write in a text file. You can write this source code file using any simple text editor (such as Notepad), or you can use the Visual Studio .NET Integrated Development Environment (IDE). Visual Studio .NET is described in Chapter 4.

Once you write your program, you compile it using the C# compiler. The end result of compiling the program is an application.