What are the keywords used to define functions in php

The keyword used to define PHP functions is "function". The syntax structure it follows is: function function_name(parameter_list) { // Function body }, where function_name is the function name, parameter_list is the parameter list, and the function body contains the code for function execution.

Keywords that define functions in PHP

In PHP, function keywords used to define functions. It is used with the following syntax:

<code>function function_name(parameter_list) {
    // 函数体
}</code>

where:

• function_name is the unique identifier of the function.
• parameter_list is an optional parameter list that specifies the input the function receives.
• Function body is the code block for function execution, which contains statements enclosed in curly braces.

Example

Define a function that calculates the sum of two numbers:

<code class="php">function sum($a, $b) {
    return $a + $b;
}

$result = sum(5, 10); // 调用函数，传递参数
echo $result; // 15</code>

Key points

• Function names should use lowercase letters and underscores.
• The function name cannot be a PHP reserved word.
• The parameters of the function can be of any data type.
• A function can return a value using the return keyword.
• Functions can call each other within the function body.
• PHP supports function overloading, allowing multiple versions to be defined with the same name, but the parameter list must be different.

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