C STL is a set of general template classes and functions, including core components such as containers, algorithms, and iterators. Containers such as vector, list, map, and set are used to store data. Vector supports random access, which is suitable for frequent reading; list insertion and deletion are efficient but accessed slowly; map and set are based on red and black trees, and automatic sorting is suitable for fast searches. Algorithms such as sort, find, copy, transform, and accumulate are commonly used to encapsulate them, and they act on the iterator range of the container. The iterator acts as a bridge connecting containers to algorithms, supporting traversal and accessing elements. Other components include function objects, adapters, allocators, which are used to customize logic, change behavior, and memory management. STL simplifies C

In C, cin and cout are used for console input and output. 1. Use cout to read the input, pay attention to type matching problems, and stop encountering spaces; 3. Use getline(cin, str) when reading strings containing spaces; 4. When using cin and getline, you need to clean the remaining characters in the buffer; 5. When entering incorrectly, you need to call cin.clear() and cin.ignore() to deal with exception status. Master these key points and write stable console programs.

FunctionhidinginC occurswhenaderivedclassdefinesafunctionwiththesamenameasabaseclassfunction,makingthebaseversioninaccessiblethroughthederivedclass.Thishappenswhenthebasefunctionisn’tvirtualorsignaturesdon’tmatchforoverriding,andnousingdeclarationis

volatile tells the compiler that the value of the variable may change at any time, preventing the compiler from optimizing access. 1. Used for hardware registers, signal handlers, or shared variables between threads (but modern C recommends std::atomic). 2. Each access is directly read and write memory instead of cached to registers. 3. It does not provide atomicity or thread safety, and only ensures that the compiler does not optimize read and write. 4. Constantly, the two are sometimes used in combination to represent read-only but externally modifyable variables. 5. It cannot replace mutexes or atomic operations, and excessive use will affect performance.

There are mainly the following methods to obtain stack traces in C: 1. Use backtrace and backtrace_symbols functions on Linux platform. By including obtaining the call stack and printing symbol information, the -rdynamic parameter needs to be added when compiling; 2. Use CaptureStackBackTrace function on Windows platform, and you need to link DbgHelp.lib and rely on PDB file to parse the function name; 3. Use third-party libraries such as GoogleBreakpad or Boost.Stacktrace to cross-platform and simplify stack capture operations; 4. In exception handling, combine the above methods to automatically output stack information in catch blocks

To call Python code in C, you must first initialize the interpreter, and then you can achieve interaction by executing strings, files, or calling specific functions. 1. Initialize the interpreter with Py_Initialize() and close it with Py_Finalize(); 2. Execute string code or PyRun_SimpleFile with PyRun_SimpleFile; 3. Import modules through PyImport_ImportModule, get the function through PyObject_GetAttrString, construct parameters of Py_BuildValue, call the function and process return

To deal with endianness issues in C, we need to clarify platform differences and take corresponding conversion measures. 1. To determine the system byte order, you can use simple functions to detect whether the current system is a little-endian; 2. When manually exchanging byte order, general conversion can be achieved through bit operations, but standard APIs such as ntohl() and htonl() are recommended; 3. Use cross-platform libraries such as Boost or absl to provide conversion interfaces, or encapsulate macros that adapt to different architectures by themselves; 4. When processing structures or buffers, you should read and convert fields by field to avoid direct reinterpret_cast structure pointer to ensure data correctness and code portability.

std::move does not actually move anything, it just converts the object to an rvalue reference, telling the compiler that the object can be used for a move operation. For example, when string assignment, if the class supports moving semantics, the target object can take over the source object resource without copying. Should be used in scenarios where resources need to be transferred and performance-sensitive, such as returning local objects, inserting containers, or exchanging ownership. However, it should not be abused, because it will degenerate into a copy without a moving structure, and the original object status is not specified after the movement. Appropriate use when passing or returning an object can avoid unnecessary copies, but if the function returns a local variable, RVO optimization may already occur, adding std::move may affect the optimization. Prone to errors include misuse on objects that still need to be used, unnecessary movements, and non-movable types