Copy and Mutablecopy

How to implement a copy

-copy:

1. Only immutable replica objects (for example: NSString) will be created

2.[nsmutablestring Copy] Product an immutable NSString object

-mutalecopy:

1. Only mutable copy objects (for example: nsmutablestring) are generated

It is concluded that as long as the copy method and the Mutalecopy method are called by nsmutable this mutable object, the new object must be generated.

Deep copy: A copy of the object will produce a new object

Shallow copy: A pointer copy does not produce a new object

If you don't understand it, it's easy to get a sense of it.

Copy and Mutablecopy