What fixed formats does php have?

php fixed formats include labels, variable declarations, function declarations, conditional statements, loop statements, array declarations, class declarations, comments, file inclusions, error handling, etc. Detailed introduction: 1. Labels, used to tell the parser which parts are PHP codes; 2. Variable declarations, you can use the "$" symbol to declare variables; 3. Function declarations, use the "function" keyword; 4. Conditional statements, Use if, else if and else keywords; 5. Loop statements, which come in many forms, including for, while, foreach, etc.

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

PHP, as a scripting language used to develop web applications, has some fixed formats and specifications. The following are some common fixed formats:

Tags: PHP code is usually included in tags between. These tags are used to tell the parser which parts are PHP code.

Variable declaration: In PHP, you can use the $ symbol to declare variables. For example, $name = "John"; declares a variable named name and assigns it the value "John".

Function declaration: Function declaration in PHP uses the function keyword. For example, function sum($a, $b) { return $a $b; } defines a function called sum that accepts two arguments, $a and $b, and returns their sum.

Conditional statements: Conditional statements in PHP use if, else if and else keywords. For example, if ($x > 0) { echo "Positive"; } else if ($x < 0) { echo "Negative"; } else { echo "Zero"; } Output different values ​​according to the value of variable $x result.

Loop statements: Loop statements in PHP come in many forms, including for, while and foreach. For example, for ($i = 0; $i < 5; $i ) { echo $i; } uses a for loop to print the numbers 0 through 4.

Array declaration: Arrays in PHP can be declared through the array() function or the simplified [] notation. For example, $fruits = array("Apple", "Banana", "Orange"); or $fruits = ["Apple", "Banana", "Orange"]; declares an array named fruits and contains three elements.

Class declaration: Classes in PHP use the class keyword. For example, class Car { public $color; function start() { echo "Car started"; } } defines a class named Car, which contains a public property color and a method start().

Comments: Comments in PHP are used to describe and explain the code. They come in two forms: single-line comments and multi-line comments. For example, // this is a single line comment, /* this is a multiline comment */.

File inclusion: You can use the include and require keywords in PHP to include the contents of other files. For example, include "header.php"; or require_once "config.php"; can include the contents of another file into the current file.

Error handling: You can use the try, catch and throw keywords in PHP to handle exceptions. For example, try { // Code block } catch (Exception $e) { // Exception handling code } can catch and handle exceptions that may occur.

The above are some common fixed formats and specifications in PHP. Developers need to comply with these formats and specifications to ensure the readability and maintainability of the code.

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