iOS Basic pen Question collection

1. What is the difference between #import和 # include?

#import是指Objective The syntax of the-C import header file to avoid duplicate import

#include是指C/c++ Import Header file, if it is objective-c and C + + implementation of a mixed, then still need to use # include to import,

In this notation, you need to add a syntax to prevent duplicate references

The role of [email protected]

@class is the declaration of a class that tells the compiler, but in the. m file still needs to be #import in, its role is only forward declaration

iOS Basic pen Question collection