chapter03notes.md

Chapter 3 - Introduction to C# App Programming

1. Comments

Single Line

Use // then type comment

Example

// Comment here 

Multi-line

Use /* */ to start and to end

Example

/* Comment here first line
   another line for commenting */

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2. using Directive

A directive that tells the compilier where to look for a class that's used in this app. These classes are organized under namespaces.

Example

using System;

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3. Blank Lines and Whitespace

Line 4 is simply a blank line. Blank lines and space characters make code easier to read, and together with tab characters are known as whitespace. Space characters and tabs are known specifically as whitespace characters. Whitespace is ignored by the compiler.

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4. Class Declaration

Every app consists of at least one class declaration that’s defined by you—the programmer. These are known as user-defined classes. The class keyword introduces a class declaration and is immediately followed by the class name. By convention, all class names begin with a capital letter and capitalize the first letter of each word they include. This is called camel case. When the first letter is capitalized, it’s known as Pascal Case.

Example of a Class Declaration

class Welcome1

Example of a Camel Case

void nameSomethingHere

Example of a Pascal Case

class FoodTesterMax

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Keywords and Contectual Keywords

ADD CHART HERE

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Class Declaration's File Name

A class declaration’s file name is usually the class name followed by the .cs file-name extension, though this is not required.

Example

FileName.cs

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Main function here

Displaying a Line of Text

Changing the Name of the App File

When changing a file name in a Visual Studio project, always do so in Visual Studio. Changing file names outside the IDE can break the project and prevent it from executing.

Displaying a Single Line of Text with Multiple Statements

Displaying Multiple Lines of Text with a Single Statement

Escape sequence

String Interpolation

Adding Integers

Prompting the User for Input, Reading a Value into Variable

Arithmetic, Arithmetic Expressions in Straight-Line Form