1 / 9

CSC 298

Learn how to write a basic C# application in this tutorial. We will cover the comment class definition, method usage, and using the System.Console class to display text on the console.

rickc
Download Presentation

CSC 298

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CSC 298 Writing a C# application

  2. A first C# application comment class definition class method use the System.Console class to write some text to the console every C# statement ends with a semi colon ; // Display Hello, world on the screen public class HelloWorld { public static void Main() { System.Console.WriteLine("Hello, world") ; } }

  3. Code organization • In C# (as in Java), no stand alone function • Code is written inside of blocks {} that are class definitions • public class HelloWorld { // my code is here … } • for now always write public class. More on this later • Good habits from Java (not required in C#) • Name the file that contains the definition of the public class HelloWorld: HelloWorld.cs • Write only onepublic class per C# file

  4. Comments • Ignored by the computer. Essential for the reader. • 2 types of comments: // and /* */ • Everything between // and the end of the line is a comment • Everything between /* and */ is a comment. It can be used on several lines. You can't nest these comments (/* blabla /* blabla */ blabla */ gives an error) • Examples • // this is a comment • /* this is a comment that can be written on several lines */ • Also XML comments /// (see VS.NET doc)

  5. The Main method • An application always start executing with the Main method (note the capital M) • The Main method must be static • It can be of type void or return an int • It can take no arguments or an array of strings • It can be of any visibility (public, private…) • public static int Main() • static void Main(String[] args) • // default to private

  6. Console Input/Output in C# • Console: a class to access I/O functionalities for the console (=DOS window) • In: input stream, Out: output stream • important static methods: • Write, WriteLine, ReadLine • Console is available in the namespace System Console.Write ("Enter your name: ");String name = Console.ReadLine();Console.WriteLine("Welcome " + name);

  7. System.Windows.Forms • A namespace that contains many classes to build graphical user interfaces • We will see many examples • Here is a simple example MessageBox.Show("Hello, world!", "Message");

  8. The using statement • Define a shortcut to write the names of classes of the FCL in our programs. • using System.Windows.Forms means: • get access to all of the classes in the namespace System.Windows.Forms • In the program, to access the class • System.Windows.Forms.MessageBox just type • MessageBox

  9. Formatting output • To concatenate strings (=sequence of characters), use + • Write("Hello, " + "World") prints • Hello, World • Write(""+1+2) is not the same as Write(1+2). Why? • For tabs and newlines, use '\t' and '\n' • Write("Hello\tWorld") prints Hello World • Write("Hello\nWorld") prints • Hello • World • See later for other ways

More Related