C# - Basic Syntax

C# – Basic Syntax :

C# is an object-oriented programming language. In Object-Oriented Programming methodology, a program consists of various objects that interact with each other by means of actions. The actions that an object may take are called methods. Objects of the same kind are said to have the same type or, more often, are said to be in the same class.

For example, let us consider a Rectangle object. It has attributes like length and width. Depending upon the design, it may need ways for accepting the values of these attributes, calculating area and display details.

Let us look at an implementation of a Rectangle class and discuss C# basic syntax, on the basis of our observations in it:

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();
 
 

When the above code is compiled and executed, it produces the following result:

Length: 4.5 Width: 3.5 Area: 15.75

The using Keyword

The first statement in any C# program is:
using System;

The class Keyword

The class keyword is used for declaring a class.

Comments in C#

Comments are used for explaining code. Compilers ignore the comment entries. The multiline comments in C# programs start with /* and terminates with the characters */ as shown below:

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

Single-line comments are indicated by the ‘//’ symbol. For example,

}//end class Rectangle

Member Variables

Variables are attributes or data members of a class, used for storing data. In the preceding program, the Rectangle class has two member variables named length and width.

Member Functions

Functions are set of statements that perform a specific task. The member functions of a class are declared within the class. Our sample class Rectangle contains three member functions: AcceptDetails, GetArea and Display.

Instantiating a Class

In the preceding program, the class ExecuteRectangle is used as a class, which contains the Main() method and instantiates the Rectangle class.

Identifiers

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:

• A name must begin with a letter that could be followed by a sequence of letters, digits (0 – 9) or underscore. The first character in an identifier cannot be a digit.


• It must not contain any embedded space or symbol like ? – +! @ # % ^ & * ( ) [ ] . ; : ” ‘ / and \. However, an underscore ( _ ) can be used.


• It should not be a C# keyword.

C# - Basic Syntax