go语言的结构体指针

package main
 
import "fmt"
 
type Books struct {
    title string
    author string
    subject string
    book_id int
}
 
func changeBook(book Books) string {   //把book对象传进来，返回的值是string类型的，也就是将被修改的值返回出来。
    book.title = "book1_change"
    return book.title
}
 
func main() {
    var book1 Books;
    book1.title = "book1"
    book1.author = "zuozhe"
    book1.book_id = 1
    var res = changeBook(book1)   //然后在外面拿到被修改的值
    book1.title = res        // 再重新赋值
    fmt.Println(book1)
}
//结果为：
{book1_change zuozhe  1}