golang结构体（结构体指针和普通结构体区别）

结构体是由一系列具有相同类型或不同类型的数据构成的数据集合。

结构体表示一项记录，比如保存图书馆的书籍记录，每本书有以下属性：

• Title ：标题

• Author ： 作者

• Subject：学科

• ID：书籍ID

  结构体知识点代码集合

结构体指针和普通结构体区别：使不使用结构体指针和使不使用指针的出发点是一样的，那就是是否试图在函数内部改变传递进来的参数的值

package main

import "fmt"

type Books struct {
   title string
   author string
   subject string
   bookId int
}
func main() {

   // 创建一个新的结构体
   fmt.Println(Books{"Go 语言", "www.runoob.com", "Go 语言教程", 6495407})

   // 也可以使用 key => value 格式
   fmt.Println(Books{title: "Go 语言", author: "www.runoob.com", subject: "Go 语言教程", bookId: 6495407})

   // 忽略的字段为 0 或 空
   fmt.Println(Books{title: "Go 语言", author: "www.runoob.com"})

   fmt.Println("----------------------------------------------------------------------------")

   var book1 Books
   var book2 Books

   book1.title = "1111fewdfew"
   book1.author = "111111fefefefef"
   book1.subject = "11111111rerererere"
   book1.bookId = 111111111111111

   book2.title = "222222frgrvr"
   book2.author = "222222grrggrgrg"
   book2.subject = "2222222ffggggghhh"
   book2.bookId = 222222222222222

   fmt.Printf("book1 title:%s\n",book1.title)
   fmt.Printf("book1 author:%s\n",book1.author)
   fmt.Printf("book1 subject:%s\n",book1.subject)
   fmt.Printf("book1 bookid:%d\n",book1.bookId)

   fmt.Printf("book2 title:%s\n",book2.title)
   fmt.Printf("book2 author:%s\n",book2.author)
   fmt.Printf("book2 subject:%s\n",book2.subject)
   fmt.Printf("book2 bookid:%d\n",book2.bookId)

   fmt.Println("-----------------------------------直接传入，修改完出来数据没变-----------------------------------------")

   printBook(book1)
   printBook(book2)

   fmt.Printf("book1 title:%s\n",book1.title)
   fmt.Printf("book1 author:%s\n",book1.author)
   fmt.Printf("book1 subject:%s\n",book1.subject)
   fmt.Printf("book1 bookid:%d\n",book1.bookId)

   fmt.Printf("book2 title:%s\n",book2.title)
   fmt.Printf("book2 author:%s\n",book2.author)
   fmt.Printf("book2 subject:%s\n",book2.subject)
   fmt.Printf("book2 bookid:%d\n",book2.bookId)
   fmt.Println("------------------------------------------指针传入，数据修改完出来，数据变了----------------------------------")

   printBook2(&book1)
   printBook2(&book2)
   fmt.Printf("book1 title:%s\n",book1.title)
   fmt.Printf("book1 author:%s\n",book1.author)
   fmt.Printf("book1 subject:%s\n",book1.subject)
   fmt.Printf("book1 bookid:%d\n",book1.bookId)

   fmt.Printf("book2 title:%s\n",book2.title)
   fmt.Printf("book2 author:%s\n",book2.author)
   fmt.Printf("book2 subject:%s\n",book2.subject)
   fmt.Printf("book2 bookid:%d\n",book2.bookId)
}
func printBook(books Books) {
   books.bookId = 0000
   fmt.Printf("book3 title:%s\n",books.title)
   fmt.Printf("book3 author:%s\n",books.author)
   fmt.Printf("book3 subject:%s\n",books.subject)
   fmt.Printf("book3 bookid:%d\n",books.bookId)
}

func printBook2( book *Books ) {
   book.bookId = 0000
   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.bookId)
}