In PHP, comments play a vital role in code documentation, readability improvement, and fostering collaboration among developers. PHP supports three primary types of comments: single-line comments, multi-line comments, and documentation comments, often known as “doc comments.”

Single-Line Comments

Single-line comments are initiated with // and extend to the end of the line. They are suitable for brief explanations or annotations within the code.

// This is a single-line comment
$name = "John"; // Assigning a value to the variable $name

Multi-Line Comments

Multi-line comments start with /* and end with */. They can span across multiple lines, making them useful for commenting out large sections of code or providing block-level descriptions.

/*
This is a multi-line comment.
It can span across multiple lines.
*/
$age = 30;

Documentation Comments (Doc Comments)

Documentation comments serve a special purpose in generating automated documentation. Typically placed above classes, functions, or methods, they follow specific formats like PHPDoc or Doxygen.

/**
 * This function calculates the sum of two numbers.
 *
 * @param int $a The first number
 * @param int $b The second number
 * @return int The sum of $a and $b
 */
function add($a, $b) {
    return $a + $b;
}

PHPDoc Tags

• @param: Describes function or method parameters.
• @return: Describes the return value.
• @var: Describes variable types.
• @throws: Describes exceptions.
• @deprecated: Indicates deprecated functions or methods.

Importance of Comments

Comments are crucial for:

• Code Documentation: They provide insights into code functionality and purpose.
• Code Readability: Well-commented code is easier to understand.
• Collaboration: They facilitate collaboration among developers by providing context within the codebase.

Best Practices

• Descriptive Comments: Explain why code exists, not just how it works.
• Updated Comments: Keep comments updated with code changes.
• Avoid Overcommenting: Comments should add value without adding noise.
• Meaningful Names: Use meaningful variable, function, and class names to minimize the need for comments.

Example

“`php
// Calculate the total price
$total = $price * $quantity;

/*
This code block retrieves user data from the database
and assigns it to the $user variable.
*/
$user = getUserData($userId);

/**

• Display a greeting message.
  *
• @param string $name The name of the user
  */
  function greet($name) {
  echo “Hello, $name!”;
  }