Can PHP functions be overloaded? If so, what are the rules?

PHP supports function overloading, allowing multiple functions to be defined with the same name, provided that the parameter lists are different. Overloading rules: the function name is the same, the function signature (parameter number, order or type) is different, the parameters must be passed by reference or value, and the return type can be different. Practical case: The calculateArea function implements square and rectangular area calculations through different signatures.

PHP Function Overloading: Rules and Practical Examples

PHP does support function overloading, allowing you to define multiple functions with the same name, provided that they The signature (parameter list) is different.

Overloading rules

The rules for PHP function overloading are as follows:

• The function names must be the same.
• The function signature must be different, that is, the number, order, or type of parameters are different.
• The return types do not need to be the same.
• Parameters to functions must be passed by reference or value.

Practical Case

The following example shows the practical application of function overloading:

<?php

function calculateArea($width, $height = null)
{
    if ($height === null) {
        // 正方形
        return $width * $width;
    } else {
        // 矩形
        return $width * $height;
    }
}

echo calculateArea(5); // 输出：25（正方形）
echo calculateArea(5, 10); // 输出：50（矩形）

Here, the calculateArea function has two different Signature:

• calculateArea(int $width): Used to calculate the area of ​​a square
• calculateArea(int $width, int $height) : Used to calculate the area of ​​a rectangle

The signatures of these functions are different, so they can be overloaded. Note that the $height parameter is optional, allowing us to calculate different areas depending on the number of parameters passed in.

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