update: 不知道用的是不是mdbook，先按mdbook的格式把代码改的符合逻辑

book/contents/basic/compound-type/struct.md

@@ -110,24 +110,30 @@ fn build_user(email: String, username: String) -> User {
 > 值的注意的是：`username`所有权被转移给了`user2`,导致了`user1`无法再被使用，但是并不代表`user1`内部的其它字段不能被继续使用，例如:
 
 ```rust
+# #[derive(Debug)]
+# struct User {
+#     active: bool,
+#     username: String,
+#     email: String,
+#     sign_in_count: u64,
+# }
+# fn main() {
 let user1 = User {
     email: String::from("someone@example.com"),
     username: String::from("someusername123"),
     active: true,
     sign_in_count: 1,
 };
-
 let user2 = User {
     active: user1.active,
     username: user1.username,
     email: String::from("another@example.com"),
     sign_in_count: user1.sign_in_count,
 };
-
 println!("{}", user1.active);
-
 // 下面这行会报错
-    //println!("{}", user1.username);
+println!("{:?}", user1);
+# }
 ```
 
 ## 结构体的内存排列