IOS multi-threaded automatic release Chichong meet question code

Synchronization: Code executes sequentially, one person performs multiple tasks, and is executed in turn. A person performs only one task at a time

Async: Multiple tasks can be performed at the same time

Process: Refers to the application running in the system, each process is independent and has a separate and secure running space

Threads: A process can have multiple threads, but only one main thread. The task of the process is done within the thread.

Process, the relationship between threads and multithreading?

Process = Company Thread = Employee Multi-Threading = Boss

Multithreading can solve the problem of program blocking, but also can improve the efficiency of program execution

Automatically release Chichong meeting question code

For (int i = 0; i < 100000; ++i) {

nsstring *str = @ "Hello World";

str = [str Stringbyappendingformat:@ "-%d", I]; string concatenation

str = [str uppercasestring]; Replace a string with uppercase

}

What happens if the number of loops is too large? How to solve it?

there will be a memory overflow, Create a large number of temporary objects inside the loop without being released

Each loop will be the last object created.

For (int i = 0; i < 100000; ++i) {

@autoreleasepool {

nsstring *str = @ "Hello World";

str = [str stringbyappendingformat:@ "-%d", I];

str = [str uppercasestring];

}

}

IOS multi-threaded automatic release Chichong meet question code