Importing header in objective c

Question

In Objective-c when we using object of one class into another class by convention we should forward declare the class in .h file, i.e. @class classname;. And sh

Answer 1

Though import of files in .m makes it easier to get away with few lines of code but it is general thinking that importing may affect the load time and response time , yes it does affect and does not.Because according to documentation by apple :-

If you are worried that including a master header file may cause your program to bloat, don’t worry. Because Mac OS X interfaces are implemented using frameworks, the code for those interfaces resides in a dynamic shared library and not in your executable. In addition, only the code used by your program is ever loaded into memory at runtime, so your in-memory footprint similarly stays small.

As for including a large number of header files during compilation, once again, don’t worry. Xcode provides a precompiled header facility to speed up compile times. By compiling all the framework headers at once, there is no need to recompile the headers unless you add a new framework. In the meantime, you can use any interface from the included frameworks with little or no performance penalty.

Thus Response and load times are affected for the first time only , But anyways forward referencing should be favoured to maintain coding standards and avoid overheads however small :).