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  Go语言 结构

  • 结构

    Go数组可让您定义可容纳相同种类的多个数据项的变量。结构是Go语言中可用的另一种用户定义的数据类型，它允许您组合不同种类的数据项。结构用于表示记录。假设您想跟踪图书馆中的书籍。您可能要跟踪每本书的以下属性-
    • 标题
    • 作者
    • 学科
    • 书号
    在这种情况下，结构非常有用。

  • 定义结构

    要定义结构，必须使用type和struct语句。struct语句定义一个新的数据类型，该程序具有多个成员。在我们的例子中，type语句将名称与struct绑定在一起。struct语句的格式如下- 
    
type struct_variable_type struct {
   member definition;
   member definition;
   ...
   member definition;
}
    定义结构类型后，即可使用以下语法将其用于声明该类型的变量。 
    
variable_name := structure_variable_type {value1, value2...valuen}

  • 访问结构成员

    要访问结构的任何成员，我们使用成员访问运算符（.）.成员访问运算符被编码为结构变量名和我们希望访问的结构成员之间的句点。您将使用struct关键字定义结构类型的变量。以下示例说明了如何使用结构- 
    
package main

import "fmt"

type Books struct {
   title string
   author string
   subject string
   book_id int
}
func main() {
   var Book1 Books    /* Declare Book1 of type Book */
   var Book2 Books    /* Declare Book2 of type Book */
 
   /* book 1 specification */
   Book1.title = "Go Programming"
   Book1.author = "Mahesh Kumar"
   Book1.subject = "Go 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 */
   fmt.Printf( "Book 1 title : %s\n", Book1.title)
   fmt.Printf( "Book 1 author : %s\n", Book1.author)
   fmt.Printf( "Book 1 subject : %s\n", Book1.subject)
   fmt.Printf( "Book 1 book_id : %d\n", Book1.book_id)

   /* print Book2 info */
   fmt.Printf( "Book 2 title : %s\n", Book2.title)
   fmt.Printf( "Book 2 author : %s\n", Book2.author)
   fmt.Printf( "Book 2 subject : %s\n", Book2.subject)
   fmt.Printf( "Book 2 book_id : %d\n", Book2.book_id)
}
    尝试一下
    编译并执行上述代码后，将产生以下结果- 
    
Book 1 title      : Go Programming
Book 1 author     : Mahesh Kumar
Book 1 subject    : Go 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

  • 结构作为函数参数

    您可以通过与传递任何其他变量或指针非常相似的方式将结构作为函数参数传递。您将以与上述示例相同的方式访问结构变量- 
    
package main

import "fmt"

type Books struct {
   title string
   author string
   subject string
   book_id int
}
func main() {
   var Book1 Books    /* Declare Book1 of type Book */
   var Book2 Books    /* Declare Book2 of type Book */
 
   /* book 1 specification */
   Book1.title = "Go Programming"
   Book1.author = "Mahesh Kumar"
   Book1.subject = "Go 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 */
   printBook(Book1)

   /* print Book2 info */
   printBook(Book2)
}
func printBook( book Books ) {
   fmt.Printf( "Book title : %s\n", book.title);
   fmt.Printf( "Book author : %s\n", book.author);
   fmt.Printf( "Book subject : %s\n", book.subject);
   fmt.Printf( "Book book_id : %d\n", book.book_id);
}
    尝试一下
    编译并执行上述代码后，将产生以下结果- 
    
Book title     : Go Programming
Book author    : Mahesh Kumar
Book subject   : Go Programming Tutorial
Book book_id   : 6495407
Book title     : Telecom Billing
Book author    : Zara Ali
Book subject   : Telecom Billing Tutorial
Book book_id   : 6495700

  • 指向结构的指针

    您可以按照与定义任何其他变量的指针相同的方式定义结构的指针，如下所示： 
    
var struct_pointer *Books
    现在，您可以将结构变量的地址存储在上面定义的指针变量中。要找到结构变量的地址，请将＆运算符放在结构名称之前，如下所示： 
    
struct_pointer = &Book1;
    要使用指向该结构的指针访问该结构的成员，必须使用“.”运算符如下- 
    
struct_pointer.title;
    让我们使用结构指针重新编写以上示例- 
    
package main

import "fmt"

type Books struct {
   title string
   author string
   subject string
   book_id int
}
func main() {
   var Book1 Books   /* Declare Book1 of type Book */
   var Book2 Books   /* Declare Book2 of type Book */
 
   /* book 1 specification */
   Book1.title = "Go Programming"
   Book1.author = "Mahesh Kumar"
   Book1.subject = "Go 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 */
   printBook(&Book1)

   /* print Book2 info */
   printBook(&Book2)
}
func printBook( book *Books ) {
   fmt.Printf( "Book title : %s\n", book.title);
   fmt.Printf( "Book author : %s\n", book.author);
   fmt.Printf( "Book subject : %s\n", book.subject);
   fmt.Printf( "Book book_id : %d\n", book.book_id);
}
    尝试一下
    编译并执行上述代码后，将产生以下结果- 
    
Book title     : Go Programming
Book author    : Mahesh Kumar
Book subject   : Go Programming Tutorial
Book book_id   : 6495407
Book title     : Telecom Billing
Book author    : Zara Ali
Book subject   : Telecom Billing Tutorial
Book book_id   : 6495700
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