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, are
said to be in the same class.
For
example, let us consider a Rectangle object. It has attributes such as length
and width. Depending upon the design, it may need ways for accepting the values
of these attributes, calculating the area, and displaying details.
Let
us look at demo of a Rectangle class and discuss C# basic syntax:
using System;
namespace RectangleDemo
{ 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
The using keyword is used for including the
namespaces in the program. A program can include multiple using statements.
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,
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 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 such as? - + ! @
# % ^ & * ( ) [ ] { } . ; : " ' / and \. However, an underscore ( _ )
can be used.
·
It should not be a C# keyword.