php自定義函數的基本語法結構

function 函數名(形參列表) {
    函數體;
    return 語句;
}

例：實現一個簡單的加、減、乘、除計算器

test.php:

<?php
require 'funcs.php';
$num1 = 56;
$num2 = 44;
$oper = "+";
$res = jisuan($num1, $num2, $oper); //調用自定義函數
echo "計算結果是：" . $res;
?>

funcs.php：

<?php
function jisuan($num1, $num2, $oper) {
    switch ($oper) {
        case "+":
            $res = $num1 + $num2;
            break;
        case "-";
            $res = $num1 - $num2;
            break;
        case "*":
            $res = $num1 * $num2;
            break;
        case "/":
            $res = $num1 / $num2;
            break;
        default:
            echo '運算符號錯誤!';
            break;
    }
    return $res;
}
?>

URL：http://www.bianceng.cn/webkf/PHP/201609/50428.htm