How to add comments in PHP? A brief analysis of common methods

In the process of writing PHP code, the role of comments is very important. Comments can help us better understand the function of the code and the implementation process. The method of adding comments in PHP is also very simple, and for different coding habits, you can use a variety of comment methods. This article will introduce how to add comments in PHP and common comment methods.

1. Single-line comments

In PHP, use // to represent single-line comments. Similar to other programming languages ​​like C, Java, etc., add a comment at the end of the line of code using // as shown below:

<?php
// 这是一行注释
echo "Hello World!";
?>

2. Multi-line comments

When we need to add multiple lines of comments to a piece of code, use the / / method.

<?php
/* 这是多行注释
   这是多行注释的第二行
*/
echo "Hello World!";
?>

3. Documentation comments

Documentation comments are to add detailed comments before code blocks such as functions, classes, interfaces, properties, etc. to facilitate others Better understand the function of these code blocks.

In PHP, use /* / to indicate documentation comments, for example:

<?php

/**
* 这是一个函数
* @param string $name
* @return string
*/
function sayHello($name) {
    return "Hello ".$name;
}

?>

4. Comment style

For comment styles, there are two main types: C style and JavaDoc style.

C-style comments use / / and / */, similar to the C programming language. JavaDoc style comments start with /, and use the @ symbol to describe the focus of the comment, for example:

<?php

/**
* This is a function.
* @param string $name Your name.
* @return string A greeting message.
*/
function sayHello($name) {
    return "Hello ".$name;
}

?>

Comments in this way can be converted into HTML through some tools as detailed documentation of functions or codes. At the same time, many integrated development environments (IDEs) support the following identifiers to parse JavaDoc comments, making them more useful in code hints and auto-completion.

In PHP 7.0 and above, in addition to JavaDoc style comments, you can also use special tags such as return value types, for example:

<?php

/**
* This is a function.
* @param string $name Your name.
* @return string A greeting message.
*/
function sayHello(string $name): string {
    return "Hello ".$name;
}

?>

You can see that the return value type tag is in the parameter It is represented by adding a colon after the list.

Summary:

In PHP, adding comments is very important, which allows us to better understand the function of the code, and also facilitates our future maintenance and Revise. Through this article, we can learn the annotation methods of different methods in PHP and the corresponding grammatical rules, which is very useful for friends who self-study PHP.

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