Joseph Albahari - C# 5.0 Pocket Reference: Instant Help for C# 5.0 Programmers

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 namespaceclass 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 lie two statements . Statements in C# execute sequentially and are terminated by a semicolon. The first statement computes the expression12 * 30 and stores the result in a local variable , named x, which is an integer type. The second statement calls the Console classs WriteLinemethod 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.

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 * 12; return inches; }}

A method can receive input data from the caller by specifying parameters and output data back to the caller by specifying a return type . We defined a method called FeetToInches that has a parameter for inputting feet, and a return type for outputting inches, both of type int (integer).

The literals30 and 100 are the arguments passed to the FeetToInches method. The Main method in our example has empty parentheses because it has no parameters, and is void because it doesnt return any value to its caller. C# recognizes a method called Main as signaling the default entry point of execution. The Main method may optionally return an integer (rather than