What are the types of php comments?

The types of php comments include single-line comments, multi-line comments, document comments, conditional comments, etc. Detailed introduction: 1. A single line comment starts with a double slash "//" and is used to comment a single line of code. In this comment type, everything from the beginning of the double slash to the end of the line will be regarded as a comment, not Will be interpreted as code; 2. Multi-line comments start with a slash asterisk "/" and end with an asterisk slash "*/". This comment type can be used to comment a piece of code or multiple lines of code; 3. Documentation comments It also starts with a slash-asterisk "/", ends with an asterisk-slash "*/", and so on.

The operating environment of this article: Windows 10 system, PHP8.1.3 version, Dell G3 computer.

In PHP, a comment is a special code segment used to explain and illustrate the function, purpose and implementation method of the program. Comments are very important to programmers because they provide assistance in understanding and maintaining the code. In PHP, there are mainly the following types of comments:

Single-line comments (//): Single-line comments start with double slashes (//) and are used to comment single lines of code. In this comment type, everything from the beginning of the double slash to the end of the line will be treated as a comment and will not be interpreted as code.

Example:

// 这是一个单行注释
$variable = 10; // 这是另一个单行注释

Multi-line comments (/* ... /): Multi-line comments start with a slash asterisk (/) and end with an asterisk-slash (*/). This comment type can be used to comment out a block of code or multiple lines of code.

Example:

/*
这是一个多行注释
可以跨越多行
*/
$variable = 10; /*
这是另一个多行注释
*/

End of documentation comment (/**…/): Documentation comments also begin with a slash asterisk (/) and end with an asterisk slash (*/). Similar to multiline comments, but documentation comments are typically used to generate documentation. Documentation comments can contain some special tags, such as @param, @return, @throws, etc., to describe the parameters, return values ​​and possible exceptions of the function.

Example:

/**
 * 这是一个文档注释示例
 *
 * @param string $name 用户名
 * @return string 欢迎消息
 * @throws Exception
 */
function welcome($name) {
    return "欢迎，" . $name . "！";
}

Conditional comments: Conditional comments are used to comment or uncomment a piece of code based on conditions. This is useful during debugging and testing phases to quickly switch blocks of code as needed.

Example:

$debug = true;
/* if ($debug) {
    echo "调试模式已启用";
} */

To sum up, the common comment types in PHP are single-line comments, multi-line comments, documentation comments and conditional comments. Based on different usage scenarios and purposes, programmers can choose appropriate annotation types to improve code readability and maintainability. The use of comments is part of good programming practice and helps team members better understand the code and provides documentation and guidance.

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