copy syntax

Reflection:OC Reflection mechanism refers to: in the running state, for any class, can know all the properties and methods of the class, for any object, can invoke its arbitrary methods and properties, this dynamic access to information and the

In the OC syntax, the Copy syntax (Copy + MutableCopy) is provided for copying objects. Among them, it is easy to confuse the shortest copy and the deep copy. The so-calledA shortest copy is an address copy.Does not generate a new object, but adds 1

The purpose of the copy design: the original object will not be affected when the copy is changed.1. a copy of an object can be created using the copy or mutablecopy method.2. Copy needs to implement the nscopying protocol first, and the created

The purpose of copy syntax: When changing a copy, it does not affect the source object;Deep copy: A copy of the content that produces a new object. The new object counter is set to 1, and the source object counter is unchanged. Shallow copy: Pointer

  Differences between copy and retain: Copy is to create a new object, retain is to create a pointer, reference object count plus 1. The Copy attribute indicates that the content of the two objects is the same. The new object retain is 1, which is

Because the database SQL statement in the major products with "dialect", that is, SQL Server Sybase are using T-SQL, MySQL is using standard SQL, Oracle has its own PL/SQL. Due to the differences in dialects, many SQL statements are difficult to

1.1 LS[syntax]: LS [-RADCXMLNOGRTUCPFBQISF1] [directory or file ...][description]: The LS command lists the files under the specified directory, the default directory is the current directory./, the default output order is in alphabetical order by

OC Syntax -- ask the specific difference between copy and retain in NSString attribute declaration, nsstringretainAsk the specific difference between copy and retain in NSString attribute declaration. copy is to release the source object, and then

MySQL user, library, table operation syntax about the user's syntax查看当前系统里的用户:select user,host from mysql.user;查看当前登陆的用户select user();创建用户语法：create user ‘用户‘@‘主机‘ identified by ‘密码‘;示例：create user ‘anuo‘@‘localhost‘ identified by ‘123‘创建用户并授权grant

Hello, C ++ (34) has a copy constructor named Dolly 6.2.4, 6.2.4 constructor.6.2.4 copy constructor In the C ++ world, in addition to using constructors to directly create a new object, you sometimes need to create a copy of an existing object, just