preface
The latest collection of the last two months of iOS interview questions summary, the answer, not detailed, after all, some questions are uncertain, if there is not understand, we leave comments to discuss, we work together!
Network module:
The history of HTTP and the HTTPS encryption process relative to HTTP
2. What are the differences and connections between TCP and UDP?
3. Where does the timeout of HTTP start by default
4. Does HTTP use UDP or TCP links and must TCP links be established every time an HTTP request is sent? Why
Q: Does TCP have a four-way handshake? Does TCP have a three-way handshake?
6. Why four handshakes?
7, TCP establishes several channels, what are they, the sender and receiver are the same channel?
Algorithm module (you can brush the LeetCode) :
1. How to determine whether a linked list is a two-way list
2. Search for questions related to rotating trees
3. Sorting arrays
4, given a string, find the longest string that does not contain repeated characters.
5. Give you a binary tree and ask you to return the values of the nodes it traverses in sequence
6, given a binary tree, find its maximum depth.
7, two stacks to implement a queue…….
The difficulty of iOS is generally in: simple medium; At present, the hard difficulty is less!
IOS module (mainly OC) :
The difference between atomic and nonatomic is atomic safe
Can a category add member variables? Why? Student: If the corresponding structure has this array of ivarList can I add a member variable why
The receiving thread and sending thread must be in the same thread
4, GCD NSThread NSOPeration use scenarios and differences, and NSOPeration states are respectively
5, block implementation principle (this is a lot of questions as long as you understand it well, this is not a problem)
Is there any difference between ARC and MRC? Why
7. Weak, strong, and weak
[super alloc] init [super alloc] init [super alloc] init]
9, object creation why init do not init is ok why
10. How many bytes does an NSobject itself take (and how does it compute), and why does Apple give objects multiples of 16 bytes? What is space for time
How NSAutoRealesepool is implemented and when to send relese messages to an object
12, app performance optimization — startup optimization said
How do YOU use NSRuntime and NSRunloop contacts
14. How to optimize image loading
What is the purpose of using dynamic libraries (dynamic libraries will increase the startup time) and how to optimize the loading process
17. Explain in detail how events are delivered and responded to (note: gestures have priority issues and how to block event delivery simultaneously).
18. What is off-screen render (the more detailed you can say, the better)
19, kVO implementation principle and how to manually trigger KVO
20. Talk about the most successful projects in the past, and introduce the technical points used in detail, and how to overcome the technical difficulties
21. Talk about copy on write
22. Protocol-oriented understanding of SWIFT
23, why are mutable arrays in Swift decorated with var
24. Talk about the non-trace buried point and how to achieve it
In 2021, good luck finding the right high-paying job
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