How to use c#? Basic syntax of c#

c#How to use? This article will introduce you to the basic syntax of C# and introduce the use of C# through simple examples. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Through the previous article [What is c#? What is the use? ], we know that C# is an object-oriented programming language.

In the object-oriented programming method, the program is composed of various objects that interact with each other through operations. The actions an object may take are called methods. Objects of the same kind are said to be of the same type, or of the same kind. [Related video tutorial recommendations: C#Tutorial]

For example, let us consider a Rectangle object. It has properties such as length and width. Depending on the design, you may need to accept the values ​​of these properties, calculate the area and display details

Let us discuss the basic syntax of C# through the implementation of the Rectangle class:

using System;
namespace RectangleApplication {
   class Rectangle {
      
      // member variables
      double length;
      double width;
      
      public void Acceptdetails() {
         length = 4.5;    
         width = 3.5;
      }
      public double GetArea() {
         return length * width; 
      }
      public void Display() {
         Console.WriteLine("Length: {0}", length);
         Console.WriteLine("Width: {0}", width);
         Console.WriteLine("Area: {0}", GetArea());
      }
   }
   class ExecuteRectangle {
      static void Main(string[] args) {
         Rectangle r = new Rectangle();
         r.Acceptdetails();
         r.Display();
         Console.ReadLine(); 
      }
   }}

Compile and When the above code is executed, the following results are produced:

Length: 4.5
Width: 3.5
Area: 15.75

using keywords

The first statement in any C# program is :

using System;

The using keyword is used to include namespaces in the program. The program can include multiple using statements.

Class keyword

The class keyword is used to declare the class.

Comments in C

#Comments are used to explain the code. Comment entries are ignored by the compiler. Multi-line comments in C# programs start with /* and end with the character */ as shown below -

/* This program demonstrates
The basic syntax of C# programming 
Language */

Single-line comments are represented by '//' symbol, for example,

//end class Rectangle

Member variables

Variables are attributes or data members of a class and are used to store data. In the previous sample program, the Rectangle class has two member variables named length and width.

Member functions

A function is a set of statements that perform a specific task. Member functions of a class are declared in the class. Our example class Rectangle contains three member functions: AcceptDetails, GetArea and Display.

Instantiate a class

In the previous sample program, the class ExecuteRectangle contains the Main() method and instantiates the Rectangle class.

Identifier

An identifier is a name used to identify a class, variable, function, or any other user-defined item. The basic rules for naming classes in C# are as follows:

1. The name must start with a letter and can be followed by a series of letters, numbers (0 - 9) or underscores. The first character in the identifier cannot be a number.

2. It cannot contain any embedded spaces or symbols, such as? -! @#%^&*()[]{}. ;: "'/ and \. However, you can use underscore (_).

3. It cannot be a C# keyword.

C# keyword

Keywords are reserved words predefined for the C# compiler. These keywords cannot be used as identifiers. However, if you want to use these keywords as identifiers, you can use the @ character Prefix keyword.

In C#, some identifiers have special meaning in the context of the code, such as get and set are called context keywords.

The following table lists C# Reserved keywords and contextual keywords in:

The above is the detailed content of How to use c#? Basic syntax of c#. For more information, please follow other related articles on the PHP Chinese website!