What is the difference between .h and .m

Improve this question. RJ86 RJ86 1 1 gold badge 2 2 silver badges 3 3 bronze badges. Add a comment. Active Oldest Votes. Actually, its very, VERY simple. So, if you had a. Improve this answer. Chris Becke Chris Becke This is the best answer. You need to take a look into Object Oriented Programming and perhaps read a little more into Objective-C development to get a good grasp on the concepts of OOP etc To answer your question "what is the difference between.

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Now live: A fully responsive profile. Linked 2. Related The method of getting and setting can only be through setValue: forKey and valueForKey to achieve. Member variables: Member variables, there are three kinds of permissions, that is, everyone knows private, protected, public, when written in the. And written in the. If you think about it further, it is easy to understand.

Naturally, it can be accessed by other. Summary: The attributes declared in the. Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search. So typically all of your interface code is known at that place. To answer these questions, the header files are usually included in the implmentation.

As the implementation imports its own header file, you can often put the other imports just there. But when do you need the import in the header file? Now the compiler needs to know something about SomeClass, but not all.

If the compiler knows that it is another class, that will be ok at this time. In the header file, no more information is needed, so the "forward declaration" of class SomeClass may suffice. Importing the complete header file for your other class works as well. So where's the downside of import? There's mainly two arguments: compile time and import cycles. Consider the little example - whenever SomeClass. This easily cascades through the complete code.

Also, obviously, any code that imports your header file will import all their imports etc. The cycles arguments works like this. Depending on what's in them, one should be known before the other I'd like to mention that the problems are a bit more relaxed with latest compilers but the basic argumentation still holds. Some more notes: The class forward declaration may be needed when you declare two types that relate to each other, i.