To allow PHP services to pass through the Windows 11 firewall, you need to create inbound rules to open the corresponding port or program. 1. Determine the port that PHP is actually listening. If the built-in server is started with php-Slocalhost:8000, the port is 8000. If using Apache or IIS, it is usually 80 or 443. 2. Open the advanced settings of "WindowsDefender Firewall", create a new inbound rule, select "Program" or "Port", fill in the PHP or Web server path or specify the port number. 3. Select Allow Connections, check the applicable network configuration file, name the rules and add a description. The IP addresses that are allowed to access, such as local network or specific IP, can be restricted through the scope. Safety

High-frequency trading is one of the most technologically-rich and capital-intensive areas in the virtual currency market. It is a competition about speed, algorithms and cutting-edge technology that ordinary market participants are hard to get involved. Understanding how it works will help us to have a deeper understanding of the complexity and specialization of the current digital asset market. For most people, it is more important to recognize and understand this phenomenon than to try it yourself.

RAII is an important technology used in resource management in C. Its core lies in automatically managing resources through the object life cycle. Its core idea is: resources are acquired at construction time and released at destruction, thereby avoiding leakage problems caused by manual release. For example, when there is no RAII, the file operation requires manually calling fclose. If there is an error in the middle or return in advance, you may forget to close the file; and after using RAII, such as the FileHandle class encapsulates the file operation, the destructor will be automatically called after leaving the scope to release the resource. 1.RAII is used in lock management (such as std::lock_guard), 2. Memory management (such as std::unique_ptr), 3. Database and network connection management, etc.

To determine whether std::optional has a value, you can use the has_value() method or directly judge in the if statement; when returning a result that may be empty, it is recommended to use std::optional to avoid null pointers and exceptions; it should not be abused, and Boolean return values or independent bool variables are more suitable in some scenarios; the initialization methods are diverse, but you need to pay attention to using reset() to clear the value, and pay attention to the life cycle and construction behavior.

There are four common methods to obtain the first element of std::vector: 1. Use the front() method to ensure that the vector is not empty, has clear semantics and is recommended for daily use; 2. Use the subscript [0], and it also needs to be judged empty, with the performance comparable to front() but slightly weaker semantics; 3. Use *begin(), which is suitable for generic programming and STL algorithms; 4. Use at(0), without manually null judgment, but low performance, and throw exceptions when crossing the boundary, which is suitable for debugging or exception handling; the best practice is to call empty() first to check whether it is empty, and then use the front() method to obtain the first element to avoid undefined behavior.

The core of PHP's development of AI text summary is to call external AI service APIs (such as OpenAI, HuggingFace) as a coordinator to realize text preprocessing, API requests, response analysis and result display; 2. The limitation is that the computing performance is weak and the AI ecosystem is weak. The response strategy is to leverage APIs, service decoupling and asynchronous processing; 3. Model selection needs to weigh summary quality, cost, delay, concurrency, data privacy, and abstract models such as GPT or BART/T5 are recommended; 4. Performance optimization includes cache, asynchronous queues, batch processing and nearby area selection. Error processing needs to cover current limit retry, network timeout, key security, input verification and logging to ensure the stable and efficient operation of the system.

Bit operation can efficiently implement the underlying operation of integers, 1. Check whether the i-th bit is 1: Use n&(1

The scope of JavaScript determines the accessibility scope of variables, which are divided into global, function and block-level scope; the context determines the direction of this and depends on the function call method. 1. Scopes include global scope (accessible anywhere), function scope (only valid within the function), and block-level scope (let and const are valid within {}). 2. The execution context contains the variable object, scope chain and the values of this. This points to global or undefined in the ordinary function, the method call points to the call object, the constructor points to the new object, and can also be explicitly specified by call/apply/bind. 3. Closure refers to functions accessing and remembering external scope variables. They are often used for encapsulation and cache, but may cause