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Summary

In this chapter, we explored the underpinnings of the .NET platform. This tour included topics covering the built-in security provided by the Common Language Runtime, along with the cross-language support and common data types. In addition, you've seen your first C# example in this book.

Chapter 3. Expressions and Control Structures

IN BRIEF

In this chapter, we will explore the basic control structures provided by C#. Each of these constructs will be explored and discussed in terms of syntax and proper usage.

WHAT YOU NEED

RECOMMENDED SOFTWARE	.NET Framework Visual Studio .NET
RECOMMENDED HARDWARE	.NET-enabled desktop client
SKILLS REQUIRED	C# coding

EXPRESSIONS AND CONTROL STRUCTURES AT A GLANCE

Expressions and Control Structures		53
Basic Expressions		53
Legal Variable Names		53
Using C# Operators		54
Pre/Post Operators		60
Program Flow Control: Control Structures		60
	The Program Execution Path	60	Short Circuit Evaluation	62
	Conditional Statements	60	Using the Ternary Operator	64
	The if Control Structure	61	The switch Statement	65
	The if/else Control Structure Combination	61
Looping		68
	The for Loop	68	The while Loop	70
	Using the for Statement	68	The do..while Loop	72
	The foreach Statement	69

Expressions and Control Structures

The goal with any programming language is to implement application logic in order to achieve the desired functionality. C# is a modern language that offers traditional expressions and control structures along with a few new ones to simplify the development process. In addition, C# is a type-safe language and enforces type safety at various levels. Such adherence to type safety is both a blessing and a curse. Depending on the language you're familiar with, some of your old habits will cause you a lot of frustration with C# because it enforces correct code and type safety. The purpose of this chapter is to explore the type safety offered by C# while delving into the expression syntax and control structures offered by the language.

Basic Expressions

An expression is defined as a syntactically correct program statement. However, for the purpose of this chapter, the expressions we're most interested in revolve around assignment and evaluation, and true/false determination. An assignment expression has at least one variable and one value to be assigned to that variable. Such is the case of declaring an integer value and assigning it the default value of 10. All variables must be initialized before use; otherwise , the C# compiler will bitterly complain about the usage of an uninitialized variable. So, what does this mean exactly? Take a look at the following C# statements :



int i;         //C# complains about the uninitialized variable





int j = 10;    //variable j has the initial value of 10




int k;




k = 10;        //okay as long as done before usage of k

C# requires all variables to be initialized before usage. The variable can be initialized during declaration or before its first usage. However, it's best to initialize a default value during its declaration; doing so will aid in future debugging attempts.

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Hoffman K., Kruger L.

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