CHAPTER 2 OVERVIEW OF C# PROGRAMMING

Naming Conventions

The C# Language Specification suggests that certain casing conventions be used in creating identifiers. Table 2-2 summarizes the suggested guidelines for casing.

For most type identifiers, the Pascal casing style is recommended. In this style, each of the words combined to make an identifier is capitalized—for example, FirstName and LastName.

Table 2-2. Recommended Identifier Naming Styles

Although these are the suggested guidelines, many organizations use other conventions— particularly in the naming of member fields, which I’ll introduce in the next chapter. Two of the common conventions are the following:

•Begin a field name with an underscore: _highTemp, _lowTemp

•Begin a field name with m_: m_highTemp, m_lowTemp

Both of these methods have the advantage of showing you immediately that these identifiers are field names. These forms also allow Visual Studio’s IntelliSense feature to group all the fields together in the pop-ups.

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CHAPTER 2 OVERVIEW OF C# PROGRAMMING

Keywords

Keywords are the character string tokens used to define the C# language. Table 2-3 gives a complete list of the C# keywords.

Some important things to know about keywords are the following:

•Keywords cannot be used as variable names or any other form of identifier, unless prefaced with the @ character.

•All C# keywords consist entirely of lowercase letters. (.NET type names, however, use Pascal casing.)

Table 2-3. The C# Keywords

Contextual keywords are identifiers that act as keywords only in certain language constructs. In those positions, they have particular meanings; but unlike keywords, which cannot ever be used as identifiers, contextual keywords can be used as identifiers in other parts of the code. Table 2-4 contains the list of contextual keywords.

Table 2-4. The C# Contextual Keywords

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CHAPTER 2 OVERVIEW OF C# PROGRAMMING

Main: The Starting Point of a Program

Every C# program must have one class with a method (function) called Main. In the SimpleProgram program shown previously, it was declared in a class called Program.

•The starting point of execution of every C# program is at the first instruction in Main.

•The name Main must be capitalized.

•The simplest form of Main is the following:

static void Main( )

{

Statements

}

Whitespace

Whitespace in a program refers to characters that do not have a visible output character. Whitespace in source code is ignored by the compiler, but is used by the programmer to make the code clearer and easier to read. Some of the whitespace characters include the following:

•Space

•Tab

•New line

•Carriage return

For example, the following code fragments are treated exactly the same by the compiler in spite of their differences in appearance.

//Nicely formatted Main()

{

Console.WriteLine("Hi, there!");

}

//Just concatenated Main(){Console.WriteLine("Hi, there!");}

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CHAPTER 2 OVERVIEW OF C# PROGRAMMING

Statements

The statements in C# are very similar to those of C and C++. This section introduces the general form of statements; the specific statement forms are covered in Chapter 9.

Simple Statements

A statement is a source code instruction describing a type or telling the program to perform an action.

•A simple statement is terminated by a semicolon.

For example, the following code is a sequence of two simple statements. The first statement defines an integer variable named var1 and initializes its value to 5. The second statement prints the value of variable var1 to a window on the screen.

int var1 = 5;

System.Console.WriteLine("The value of var1 is {0}", var1);

Blocks

A block is a sequence of zero or more statements enclosed by a matching set of curly braces; it acts as a single syntactic statement.

You can create a block from the set of two statements in the preceding example by enclosing the statements in matching curly braces, as shown in the following code:

{

int var1 = 5;

System.Console.WriteLine("The value of var1 is {0}", var1);

}

Some important things to know about blocks are the following:

•You can use a block whenever the syntax requires a statement but the action you need requires more than one simple statement.

•Certain program constructs require blocks. In these constructs, you cannot substitute a simple statement for the block.

•Although a simple statement is terminated by a semicolon, a block is not followed by a semicolon. (Actually, the compiler will allow it—but it’s not good style.)

{Terminating semicolon

System.Console.WriteLine("The value of var1 is {0}", var1);

}

↑ No terminating semicolon

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