How do PHP functions call other functions?

In PHP, you can use the call_user_func() function to call other functions, which requires two parameters: the function name and an array containing the function parameters. Define the function name to be called. Put the function parameters into an array. Use call_user_func() to call the function.

PHP functions call other functions

In PHP, you can use the built-in call_user_func() function to call other functions. call_user_func() Accepts two parameters: the name of the function to be called and an array containing the function parameters.

<?php
// 定义一个函数
function addNumbers($a, $b) {
    return $a + $b;
}

// 使用 call_user_func() 调用函数
$result = call_user_func('addNumbers', 10, 20);

// 输出结果
echo $result; // 输出：30
?>

Practical case: Calculate the total amount

The following is a practical case using call_user_func() to calculate the total amount of all items in the shopping basket:

<?php
// 定义一个函数来计算单个商品的总额
function calculateItemTotal($item) {
    // 获取商品价格和数量
    $price = $item['price'];
    $quantity = $item['quantity'];

    // 计算总额
    $total = $price * $quantity;

    // 返回总额
    return $total;
}

// 获取购物篮中的商品
$shoppingCart = [
    ['name' => 'Apple', 'price' => 1.00, 'quantity' => 2],
    ['name' => 'Orange', 'price' => 1.50, 'quantity' => 3],
    ['name' => 'Banana', 'price' => 2.00, 'quantity' => 1]
];

// 计算总额
$totalSum = 0;
foreach ($shoppingCart as $item) {
    // 使用 call_user_func() 调用 calculateItemTotal() 函数
    $itemTotal = call_user_func('calculateItemTotal', $item);

    // 将商品总额添加到总和中
    $totalSum += $itemTotal;
}

// 输出总额
echo $totalSum; // 输出：8.50
?>

This approach provides greater flexibility as it allows you to dynamically specify the function to be called and pass arguments.

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