Introduction to C# programming language: why learn by comparing with C, C++, Java

C# is designed for the Common Language Infrastructure (CLI), which describes executable code and runtime environment. This allows usage of multiple high-level languages on various computer platforms and architectures. Common Language Runtime (CLR) is defined in the Common Language Infrastructure (CLI). CLR is the Virtual Machine component managing the execution of programs written in languages [ [ ...]

Object-Oriented Basics in C#

This chapter introduces object-oriented programming. Those who are familiar with object- oriented programming will probably want to skip this chapter. You can take many approaches to object-oriented design, as evidenced by the number of books written about it. The following introduction takes a fairly pragmatic approach and doesn’t spend a lot of time on design, [ [ ...]

The .NET Runtime Environment with C#

In the past, writing modules that could be called from multiple languages was difficult. Code that’s written in Visual Basic can’t be called from Visual C++. Code that’s written in Visual C++ can sometimes be called from Visual Basic, but it’s not easy to do. Visual C++ uses the C and C++ runtimes, which have [ [ ...]

C# Quick Start

1. Hello, Universe As a supporter of SETI, we thought it’d be appropriate to do a “Hello, Universe” program rather than the canonical “Hello, World” program: using System; class Hello { public static void Main(string[] args) { Console.WriteLine(“Hello, Universe”); // iterate over command-line arguments, // and print them out for (int arg = 0; arg < [ [ ...]

Developing in C#

To program in C#, you’re going to need a way to build C# programs. You can do this with a command-line compiler, VS .NET, or a C# package for a programming editor. 1. The Command-Line Compiler The simplest way to get started writing C# code is by using the .NET runtime and Framework’s SDK. The [ [ ...]

Exception Handling in C#

In many programming books, exception handling warrants a chapter somewhat late in the book. In this book, however, it’s near the front for a couple of reasons. The first reason is that exception handling is deeply ingrained in the .NET runtime and is therefore common in C# code. C++ code can be written without using [ [ ...]

Classes 101 in C#

Classes are the heart of any application in an object-oriented language. This chapter is broken into several sections. The first section describes the parts of C# you’ll use often, and the later sections describe features you won’t use as often, depending on what kind of code you’re writing. 1. A Simple Class A C# class [ [ ...]

Base Classes and Inheritance in C#

1. The Engineer Class The following class implements Engineer and methods to handle billing for Engineer: using System; class Engineer { // constructor public Engineer(string name, float billingRate) { this.name = name; this.billingRate = billingRate; } // figure out the charge based on engineer’s rate public float CalculateCharge(float hours) { return(hours * billingRate); } // [ [ ...]

Member Accessibility and Overloading in C#

One of the important decisions to make when designing an object is how accessible to make the members. In C#, you can control accessibility in several ways. 1. Class Accessibility The coarsest level at which accessibility can be controlled is at the class. In most cases, the only valid modifiers on a class are public, [ [ ...]

Other Class Details in C#

This chapter discusses some of the miscellaneous issues of classes, including constructors, nesting, and overloading rules. 1. Nested Classes Sometimes it’s convenient to nest classes within other classes, such as when a helper class is used by only one other class. The accessibility of the nested class follows similar rules to the ones outlined in [ [ ...]

Structs (Value Types) in C#

1. A Point Struct In a graphics system, a value class could encapsulate a point. Here’s how you’d declare it: using System; struct Point { public Point(int x, int y) { this.x = x; this.y = y; } public override string ToString() { return(String.Format(“({0}, {1})”, x, y)); } public int x; public int y; } [ [ ...]

Structs (Value Types) in C#: Working with Interfaces

1. Working with Interfaces Typically, code doesn’t know whether an object supports an interface, so it needs to check whether the object implements the interface before doing the cast: using System; interface IScalable { void ScaleX(float factor); void ScaleY(float factor); } public class DiagramObject { public DiagramObject() {} } public class TextObject: DiagramObject, IScalable { [ [ ...]

Versioning and Aliases with C#

A software project rarely exists as a single version of code that’s never revised, unless the soft­ware never sees the light of day. In most cases, the software library writer is going to want to change some things, and the client will need to adapt to such changes. Dealing with such issues is known as [ [ ...]

Selection Statements: if and switch

The selection statements perform operations based on the value of an expression. 1. if The if statement in C# requires that the condition inside the if statement evaluate to an expression of type bool. In other words, the following is illegal: // error using System; class Test { public static void Main() { int value; [ [ ...]

Iteration Statements: while, do, for and foreach

Iteration statements are often known as looping statements, and they perform operations while a specific condition is true. 1. while The while loop functions as expected: while the condition is true, the loop is executed. Like the if statement, the while requires a Boolean condition: using System; class Test { public static void Main() { [ [ ...]

Jump Statements: break, continue, goto, return

Jump statements are used to do just that—jump from one statement to another. break The break statement breaks out of the current iteration or switch statement and continues execution after that statement. continue The continue statement skips all the later lines in the current iteration statement and then continues executing the iteration statement. goto The [ [ ...]

Other Statements: lock, using, try-catch-finally, checked/unchecked, and yield

The following statements are covered in other chapters. lock The lock statement provides exclusive access to a thread; see Chapter 31. using The using statement is used in two ways. The first is to specify namespaces, which is covered in Chapter 3. The second use is to ensure that Dispose() is called at the end [ [ ...]

Variable Scoping and Definite Assignment

In C#, you can give local variables only those names that allow them to be uniquely identified in a given scope. If a name has more than one meaning in a scope and you have no way to disambiguate the name, the innermost declaration of the name is an error and you must change it. [ [ ...]

Operators and Expressions in C#

The C# expression syntax is based upon the C++ expression syntax. 1. Operator Precedence When an expression contains multiple operators, the precedence of the operators controls the order in which the elements of the expression are evaluated. You can change the default prece­dence by grouping elements with parentheses, like so: int value = 1 + [ [ ...]

CHAPTER 15 Conversions in C#

In C#, conversions are divided into implicit and explicit conversions. Implicit conversions are those that will always succeed; the conversion can always be performed without data loss. For numeric types, this means the destination type can fully represent the range of the source type. For example, a short can be converted implicitly to an int, because [ [ ...]