Csharp 简明教程
C
在 C# 中,结构是一种值类型数据类型。它可以让你将多个不同数据类型的相关数据保存在一个变量中。使用 struct 关键字可以创建一个结构。
In C#, a structure is a value type data type. It helps you to make a single variable hold related data of various data types. The struct keyword is used for creating a structure.
结构用于表示记录。假设你想跟踪一个图书馆内的书籍。你可能希望跟踪关于每本书的以下属性:
Structures are used to represent a record. Suppose you want to keep track of your books in a library. You might want to track the following attributes about each book −
-
Title
-
Author
-
Subject
-
Book ID
Defining a Structure
要定义一个结构,必须使用 struct 语句。struct 语句为你的程序定义了一个新的数据类型,它包含多个成员。
To define a structure, you must use the struct statement. The struct statement defines a new data type, with more than one member for your program.
例如,以下是如何声明一个 Book 结构:
For example, here is the way you can declare the Book structure −
struct Books {
public string title;
public string author;
public string subject;
public int book_id;
};
以下程序演示了结构的用法:
The following program shows the use of the structure −
using System;
struct Books {
public string title;
public string author;
public string subject;
public int book_id;
};
public class testStructure {
public static void Main(string[] args) {
Books Book1; /* Declare Book1 of type Book */
Books Book2; /* Declare Book2 of type Book */
/* book 1 specification */
Book1.title = "C Programming";
Book1.author = "Nuha Ali";
Book1.subject = "C Programming Tutorial";
Book1.book_id = 6495407;
/* book 2 specification */
Book2.title = "Telecom Billing";
Book2.author = "Zara Ali";
Book2.subject = "Telecom Billing Tutorial";
Book2.book_id = 6495700;
/* print Book1 info */
Console.WriteLine( "Book 1 title : {0}", Book1.title);
Console.WriteLine("Book 1 author : {0}", Book1.author);
Console.WriteLine("Book 1 subject : {0}", Book1.subject);
Console.WriteLine("Book 1 book_id :{0}", Book1.book_id);
/* print Book2 info */
Console.WriteLine("Book 2 title : {0}", Book2.title);
Console.WriteLine("Book 2 author : {0}", Book2.author);
Console.WriteLine("Book 2 subject : {0}", Book2.subject);
Console.WriteLine("Book 2 book_id : {0}", Book2.book_id);
Console.ReadKey();
}
}
编译并执行上述代码后,将产生以下结果 −
When the above code is compiled and executed, it produces the following result −
Book 1 title : C Programming
Book 1 author : Nuha Ali
Book 1 subject : C Programming Tutorial
Book 1 book_id : 6495407
Book 2 title : Telecom Billing
Book 2 author : Zara Ali
Book 2 subject : Telecom Billing Tutorial
Book 2 book_id : 6495700
Features of C
你已经使用了一个名为 Books 的简单结构。C# 中的结构与传统 C 或 C++ 中的结构非常不同。C# 结构具有以下特点:
You have already used a simple structure named Books. Structures in C# are quite different from that in traditional C or C++. The C# structures have the following features −
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Structures can have methods, fields, indexers, properties, operator methods, and events.
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Structures can have defined constructors, but not destructors. However, you cannot define a default constructor for a structure. The default constructor is automatically defined and cannot be changed.
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Unlike classes, structures cannot inherit other structures or classes.
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Structures cannot be used as a base for other structures or classes.
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A structure can implement one or more interfaces.
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Structure members cannot be specified as abstract, virtual, or protected.
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When you create a struct object using the New operator, it gets created and the appropriate constructor is called. Unlike classes, structs can be instantiated without using the New operator.
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If the New operator is not used, the fields remain unassigned and the object cannot be used until all the fields are initialized.
Class versus Structure
类和结构有以下基本差异 −
Classes and Structures have the following basic differences −
-
classes are reference types and structs are value types
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structures do not support inheritance
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structures cannot have default constructor
鉴于上述讨论,让我们重写先前的示例 −
In the light of the above discussions, let us rewrite the previous example −
using System;
struct Books {
private string title;
private string author;
private string subject;
private int book_id;
public void getValues(string t, string a, string s, int id) {
title = t;
author = a;
subject = s;
book_id = id;
}
public void display() {
Console.WriteLine("Title : {0}", title);
Console.WriteLine("Author : {0}", author);
Console.WriteLine("Subject : {0}", subject);
Console.WriteLine("Book_id :{0}", book_id);
}
};
public class testStructure {
public static void Main(string[] args) {
Books Book1 = new Books(); /* Declare Book1 of type Book */
Books Book2 = new Books(); /* Declare Book2 of type Book */
/* book 1 specification */
Book1.getValues("C Programming",
"Nuha Ali", "C Programming Tutorial",6495407);
/* book 2 specification */
Book2.getValues("Telecom Billing",
"Zara Ali", "Telecom Billing Tutorial", 6495700);
/* print Book1 info */
Book1.display();
/* print Book2 info */
Book2.display();
Console.ReadKey();
}
}
编译并执行上述代码后,将产生以下结果 −
When the above code is compiled and executed, it produces the following result −
Title : C Programming
Author : Nuha Ali
Subject : C Programming Tutorial
Book_id : 6495407
Title : Telecom Billing
Author : Zara Ali
Subject : Telecom Billing Tutorial
Book_id : 6495700