Comparison of C++ function memory allocation and destruction and garbage collection mechanism

The basic usage of std::vector includes: 1. Declare vector; 2. Add elements with push_back(); 3. Initialize with initialization list; 4. Loop traversal with range for; 5. Access elements through index or back(); 6. Direct assignment of values to modify elements; 7. Delete the end elements with pop_back(); 8. Call size() to get the number of elements; it is recommended to use constauto& to avoid copying, pre-allocate reserve() to improve performance, and pay attention to checking that it is not empty before access. This data structure is an efficient and preferred way to handle string lists.

ClassmethodsinPythonareboundtotheclassandnottoinstances,allowingthemtobecalledwithoutcreatinganobject.1.Theyaredefinedusingthe@classmethoddecoratorandtakeclsasthefirstparameter,referringtotheclassitself.2.Theycanaccessclassvariablesandarecommonlyused

asyncio.Queue is a queue tool for secure communication between asynchronous tasks. 1. The producer adds data through awaitqueue.put(item), and the consumer uses awaitqueue.get() to obtain data; 2. For each item you process, you need to call queue.task_done() to wait for queue.join() to complete all tasks; 3. Use None as the end signal to notify the consumer to stop; 4. When multiple consumers, multiple end signals need to be sent or all tasks have been processed before canceling the task; 5. The queue supports setting maxsize limit capacity, put and get operations automatically suspend and do not block the event loop, and the program finally passes Canc

std::accumulateinC sumselementsbyincludingtheheaderandusingthesyntaxstd::accumulate(start_iterator,end_iterator,initial_value),wheretheinitialvaluemustmatchtheresulttypetoavoidprecisionloss,anditworkssafelywithemptycontainersbyreturningtheinitialval

In C, the method of passing parameters affects performance, security and modification of original data: use the value when passing basic types or when there is no modification, use the reference when large objects and when modifying, use the reference when reading large objects, and use const reference when reading large objects, avoid returning references to local variables to ensure efficiency and security.

To link libraries in C, you need to use -L to specify the library path when compiling, -l to specify the library name, and use -I to include the header file path to ensure that the static or dynamic library files exist and are named correctly. If necessary, embed the runtime library path through -Wl,-rpath, so that the compiler can find the declaration, the linker can find the implementation, and the program can be successfully built and run.

To accurately measure the execution time of C code, you should use the steady_clock or high_resolution_clock in the std::chrono library; 1. Contain the header file and call std::chrono::steady_clock::now() to record the starting time point; 2. Execute the code to be tested; 3. Call now() again to get the end time point; 4. Calculate the time difference and use duration_cast to convert it into units such as nanoseconds, microseconds or milliseconds; 5. For extremely fast operations, you need to loop and execute multiple times before taking the average value to improve accuracy; 6. Always measure in the Release mode with optimization enabled to avoid debug mode and invalid code elimination

Deep copy will copy the dynamic memory pointed to by the pointer, while shallow copy only copy the pointer itself, causing multiple objects to share the same piece of memory; 1. shallow copy risk: the default copy constructor performs shallow copy, so that the data of str1 and str2 point to the same memory, causing double release crash during destruction; 2. Deep copy solution: Customize copy constructor and assignment operator, allocate new memory to data and copy content to ensure the object is independent; 3. Recommended practices: follow RuleofThree, explicitly define destructors, copy constructors and assignment operators when manually managing resources; 4. Modern C recommends: use std::string or smart pointer to automatically realize deep copy to avoid manual memory management problems, and ensure safe and efficient