C# 3.0 in a Nutshell, 3rd Edition

Chapter 2. C# Language Basics

In this chapter, we introduce the basics of the C# language.

A First C# Program

Here is a program that multiplies 12 by 30, and prints the result, 360, to the screen. The double-forward slash indicates that the remainder of a line is a comment.

using System;                     // importing namespace

class Test                        // class declaration
{
  static void Main (  )             //   method declaration
  {
    int x = 12 * 30;              //     statement 1
    Console.WriteLine (x);        //     statement 2
  }                               //   end of method
}                                 // end of class

At the heart of this program lies two statements. Statements in C# execute sequentially. Each statement is terminated by a semicolon:

    int x = 12 * 30;
    Console.WriteLine (x);

The first statement computes the expression 12 * 30 and stores the result in a local variable, named x, which is an integer type. The second statement calls the Console class’s WriteLine method, to print the variable x to a text window on the screen.

A method performs an action in a series of statements, called a statement block —a pair of braces containing zero or more statements. We defined a single method named Main:

  static void Main (  )
  {
    ...
  }

Writing higher-level functions that call upon lower-level functions simplifies a program. We can refactor our program with a reusable method that multiplies an integer by 12 as follows:

using System; class Test { static void Main ( ) { Console.WriteLine (FeetToInches (30)); // 360 Console.WriteLine (FeetToInches (100)); // 1200 } static int FeetToInches (int feet) { int inches = feet ...