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iOS Objective-C Basics (Retired) Advanced Objective-C Dynamic Typing

Marc Zovighian
Marc Zovighian
1,664 Points
Posted by Marc Zovighian
Marc Zovighian
1,664 Points

How come we dont need to write *thing?

for (id thing in mixed)

why didnt we write for(id *thing in mixed) instead? Since thing is always going to be an object, isnt better for memory management to use a pointer to that object instead of the object?

1 Answer

Andres Oliva
Andres Oliva
7,810 Points
Andres Oliva
Andres Oliva
7,810 Points

We don't use * because id itself is a pointer.

For example:

NSString *s = @"x"; id obj = s;

In reality, *s = @"x", but s may be equal to 0xF226ACB2 (just saying), because s is a pointer to a memory address, whereas *s is the thing that s points to.

Basically, id is a pointer to an object of unknown/unspecified type.

Marc Zovighian
Marc Zovighian
1,664 Points
Marc Zovighian
Marc Zovighian
1,664 Points

Makes sense! Thanks a lot!