CustomAttributes are mechanisms used in C# to attach metadata to code elements. Its core function is to inherit the System.Attribute class and read through reflection at runtime to implement functions such as logging, permission control, etc. Specifically, it includes: 1. CustomAttributes are declarative information, which exists in the form of feature classes, and are often used to mark classes, methods, etc.; 2. When creating, you need to define a class inherited from Attribute, and use AttributeUsage to specify the application target; 3. After application, you can obtain feature information through reflection, such as using Attribute.GetCustomAttribute();

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

When processing large amounts of data, C# can be efficient through streaming, parallel asynchronous and appropriate data structures. 1. Use streaming processing to read one by one or in batches, such as StreamReader or EFCore's AsAsyncEnumerable to avoid memory overflow; 2. Use parallel (Parallel.ForEach/PLINQ) and asynchronous (async/await Task.Run) reasonably to control the number of concurrency and pay attention to thread safety; 3. Select efficient data structures (such as Dictionary, HashSet) and serialization libraries (such as System.Text.Json, MessagePack) to reduce search time and serialization overhead.

In C, the POD (PlainOldData) type refers to a type with a simple structure and compatible with C language data processing. It needs to meet two conditions: it has ordinary copy semantics, which can be copied by memcpy; it has a standard layout and the memory structure is predictable. Specific requirements include: all non-static members are public, no user-defined constructors or destructors, no virtual functions or base classes, and all non-static members themselves are PODs. For example structPoint{intx;inty;} is POD. Its uses include binary I/O, C interoperability, performance optimization, etc. You can check whether the type is POD through std::is_pod, but it is recommended to use std::is_trivia after C 11.

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

The key to writing C# code well is maintainability and testability. Reasonably divide responsibilities, follow the single responsibility principle (SRP), and take data access, business logic and request processing by Repository, Service and Controller respectively to improve structural clarity and testing efficiency. Multi-purpose interface and dependency injection (DI) facilitate replacement implementation, extension of functions and simulation testing. Unit testing should isolate external dependencies and use Mock tools to verify logic to ensure fast and stable execution. Standardize naming and splitting small functions to improve readability and maintenance efficiency. Adhering to the principles of clear structure, clear responsibilities and test-friendly can significantly improve development efficiency and code quality.

The iterator in C is a tool for traversing container elements, which acts as a bridge between the container and the algorithm. It accesses and manipulates data like a pointer without manually managing indexes. Iterator types include: 1. Input iterator (read-only, forward); 2. Output iterator (write-only, forward); 3. Forward iterator (read-write, multi-pass support); 4. Bidirectional iterator (movable forward and backward, such as list, set); 5. Random access iterator (fastest, such as vector, deque). Using iterators can abstract container implementation details, improve code flexibility and reusability, and be compatible with standard library functions such as std::copy and std::transform. Common errors include: dereference invalid iterator, mixed use