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Why do you stand out from the talented IOS developers?
How can I challenge the limits far from the job requirements?
How can I succeed at Xinyi?
So what are your tricks?
In this market where iOS posts are in short supply, the requirements for iOS developers are growing. Let's share our recent experiences with recruiters and release 47 Interview Questions and answers for the reference of IOS developers.

Bottom Layer:

1. What is the relationship between runloop and thread?
2. Have you ever touched the reflection mechanism in oc? Brief Introduction to concepts and usage
3. What are the essential differences and connections between class methods and instance methods in objc?
4. What is the role of runloop mode?
5. What is 1 runloop?
6. ID and instanncetype
7. What are GDB and lldb?
8. Simulate stack operations
9. Have you ever touched the reflection mechanism in oc? Brief Introduction to concepts and usage
10. Do LDB (GDB) commonly used Debugging commands?
11. The block is usually modified with that keyword. Why? Which situations will cause block loop reference? How can this problem be solved?
12. why are many built-in classes, for example, the delegate attribute of tableviewcontroller is assign rather than retain?
13. When is didreceivememorywarning of viewcontroller called? What is the default operation?
14. When block is used, what will happen to the reference loop? How can this problem be solved?
15. How to Use user defined runtime attributes in IB?

Basics:

16. Weak and unowned
17. What are GDB and lldb?
18. Role of the static Keyword:
19. How does objective-C manage the memory? What are your opinions and solutions?
20. What are the principles of memory management? According to the default rule, which keywords need to be manually released? How can we effectively avoid Memory leakage when combined with property?
21. nsoperation queue?
22. What is delayed loading?
23. Under what circumstances does bad_access appear?
24. What is 0x8badf00d?
25. What is the difference between GCD and nsoperation?
26. What are the advantages and disadvantages of a single instance?
27. Relationship between runloop and thread: How can a subthread not destroy a task after it is executed?
28. Comparison between nonatomic and atomic: your understanding of them.
29. Communication Methods between two objects
30. How to store OS data? Does the SQLite database support writing data from multiple threads? If not, how can this problem be solved?
31. If a function is executed for 10 times and the secondary result is incorrect for eight times, how should you check the bug.
32, 1-1000 digits, the order is disordered, and three digits are lost to find the three missing digits.
33. Is there a private Method for Object-C? What about private variables?
34. What is the difference between stack and stack?
35. Can I add instance variables to the compiled class? Can I add instance variables to the class created at runtime? Why?
36. How can I use GCD to synchronize several asynchronous calls? (For example, load multiple images asynchronously based on several URLs, and then synthesize an entire image after all the images are downloaded)
37. What is the role of dispatch_barrier_async?

Framework:

38. Third-party memory leak detection tool: mleaksfinder Principle Analysis
39. Escape Closure
40. Cocoa touch framework

Network:

41. http protocol details
42. Talk about your understanding of HTTP, TCP, IP, and socket protocols

Test:

43. unit tests!
44. Why is this unit test used? What benefits does it bring to us?
45. Importance of unit testing:

SWIFT:

46. swift closure
47. Map usage of higher-order functions in swift

Answer:

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I have already recruited people, and I have learned how to add answers to 47 interview questions.