The basic syntax for C #
C # is an object-oriented programming language. In object-oriented programming approach, the program consists of the composition of the various objects interact with each other. The same kinds of objects typically have the same type, or that is in the same class.
For example, Rectangle (rectangular) objects for example. It has a length and width attributes. By design, it may be necessary to accept the values of these properties, calculate the area and show details.
Let's look at the realization of a Rectangle (rectangular) classes, and to discuss the basic C # syntax:
using System; namespace RectangleApplication { class Rectangle { // Member variable 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 results:
Length: 4.5 Width: 3.5 Area: 15.75
usingkeywords
At any C # program in the first statement is:
using System;
using keywords for inclusion in the program namespace.A program can contain multiple using statements.
classkeyword
class keyword is used to declare a class.
Comments in C #
Comments are used to interpret the code. The compiler will ignore the comment entry. In C # program, a multi-line comments begin with / *, and the characters * / termination, as follows:
/ * This program demonstrates The basic syntax of C # programming Language * /
Single-line comments with '@' symbol. E.g:
} // End class Rectangle
Member variables
Variable is a property or data member of a class, for storing data. In the aboveprocedure,Rectangle class has two member variables namedlengthandwidth.
Member function
Function is a series of statements to perform a given task. Class member functions are declared in the class. We illustrate the Rectangle class contains three memberfunctions:AcceptDetails, GetArea andDisplay.
Instantiate a class
In the above program, the classExecuteRectangleis aMain ()method of the class and instance of theRectangleclass contains.
Identifiers
Identifier is used to identify a class, variable, function, or any other user-defined items. In C #, class name must follow these basic rules:
- The identifier must begin with a letter, it can be followed by a series of letters, numbers (0 - 9) or an underscore (_). Identifiers first character can not be a number.
- The identifier must not contain any embedded spaces or symbols, such as - + @ #% ^ & * () [] {};:?! " '/ \ However, you can use an underscore (_)/en.
- Identifiers can not be C # keywords.
C # Keywords
Keywords are the C # compiler predefined reserved words. These keywords can not be used as identifiers, but if you want to use these keywords as identifiers, in front of the keyword @ character as a prefix.
In C #, and some identifiers have special significance in the context of the code, such as get and set, these are called contextual keyword (contextual keywords).
The following table lists reserved keywords in C # (Reserved Keywords) and contextual keyword (Contextual Keywords):
保留关键字 | ||||||
abstract | as | base | bool | break | byte | case |
catch | char | checked | class | const | continue | decimal |
default | delegate | do | double | else | enum | event |
explicit | extern | false | finally | fixed | float | for |
foreach | goto | if | implicit | in | in (generic modifier) | int |
interface | internal | is | lock | long | namespace | new |
null | object | operator | out | out (generic modifier) | override | params |
private | protected | public | readonly | ref | return | sbyte |
sealed | short | sizeof | stackalloc | static | string | struct |
switch | this | throw | true | try | typeof | uint |
ulong | unchecked | unsafe | ushort | using | virtual | void |
volatile | while | |||||
上下文关键字 | ||||||
add | alias | ascending | descending | dynamic | from | get |
global | group | into | join | let | orderby | partial (type) |
partial (method) | remove | select | set |