Question

as the title says, what is the difference between a pointer and an object.

Say I have this code..

NSString *red = [[NSString alloc]initWithFormat:@"%@"];

and this code..

NSString *blue = [NSString stringWithFormat:@"%@"];

Is it correct to assume that they’re both pointers to an object and pretty much the same? And if so, how should I think of objects in my mind ?

I do apologize if the answer exists already, I did use the search function but I’ve only found examples of this in the C++ language and wanted to make sure how it was in objective-c.

Answer 1

In addition to Basile Starynkevitch and Bram’s answer,

In objective C the difference between your code line is,

NSString *red = [[NSString alloc]initWithFormat:@"%@"];

**Above code says you own red object so it’s your responsibility to release it.

NSString *blue = [NSString stringWithFormat:@"%@"];

**You don’t own it someone else in your program deep down inside will own this and you don’t have to release this.

I would suggest for more information reading Apple’s documentation is GREAT! specially Learning, “Objective C programming guide”

Good luck!

PS : iOS 5 has new feature, memory management is done by iOS itself, Now developer can be more creative instead doing 3 grade mathematics of reference counting 🙂