php - OOP 问题停止 PHP 运行和 MySQL 数据数组检索问题

Question

现在，StackOverflow 的使用帮助我解决了很多问题，但是在准备好之前我的代码还存在两个问题，任何想法都很棒，因为我目前正在尖叫:

首先，我使用以下方法尝试从 MySQL 数据库中提取数据，将其作为数字数组返回并按 ID 排序。那里有 2 项，无论我做什么，我只能显示 1 项(当表格填满更多时，我需要它显示所有数据):

$query = "SELECT * FROM batch ORDER by ID";
$result = $mysqli->query($query);

/* numeric array */
$row = $result->fetch_array(MYSQLI_NUM);
printf ("%s (%s)\n", $row[0], $row[1]);

?> 

其次，有点偏离主题，但下面的代码是由 StackOverflow 用户给出的，但是我无法让它工作，他们已经将其调整为 OOP，这不是我熟悉的领域，无论我做什么纠正 $this-> 或 public/private 它仍然拒绝工作(代码的目的是在$userinput 会根据 $widgetBatches 数组检查最接近的匹配(即输入是 1100，最接近的是 1000)，然后从输入中扣除(留下 100)，并且该过程再次循环进行检查，这次返回 100 作为最接近，此过程将继续，直到 $userinput 达到 0 或负数:

<?php

$userinput = 10000; // Our magic variable - user input

$iterations = 0;

function Widget($userinput)
{
    $this->iterations++;
    $widgetRequested = $userinput;
    $widgetBatches = array("250", "500", "1000", "2000");

    echo "Iteration " . $iterations;
    echo "<br/>";

    echo "Widget requested: " . $widgetRequested;
    echo "<br/>";

    $closest = GetClosest($widgetBatches, $widgetRequested);
    echo "Closest: " . $closest;
    echo "<br/>";

    $widgetRemaining = $widgetRequested - $closest;
    echo "Remainder: " . $widgetRemaining;

    echo "<hr/>";
    if($widgetRemaining > 0)
    {
        Widget($widgetRemaining);
    }
    else
    {
        echo "The value is now below or equaling zero: " . $widgetRemaining . "!";
    }
}

function GetClosest($array, $value)
{
    $lowest = null;
    foreach($array as $val)
    {
        if($lowest == null || abs($value - $lowest) > abs($val - $value))
        {
            $lowest = $val;
        }
    }
    return $lowest;
}


?>

Answer 1

这个:

<?php

function Widget($input) {
    $currentValue = $input; // Set internal variable from input (Think of this as an initial "remainder")
    $i = 0;
    $widgetBatches = [250, 500, 1000, 2000]; // Setup batch array

    while ($currentValue > 0) { // While the remainder is more than 0
        $i++;
        echo "Iteration " . $i . "<br/>";
        echo "Widget requested: " . $currentValue . "<br/>";
        $closest = GetClosest($widgetBatches, $currentValue); // Find the closest value from batch array
        echo "Closest: " . $closest . "<br/>";
        $currentValue = $currentValue - $closest; // Work out new remainder
        echo "Remainder: " . $currentValue . "<hr/>";
    }

    // Loop will exit when remainder is less than 0
    echo "The value is now below or equaling zero: " . $currentValue . "!";
}

function GetClosest($array, $value) {
    $result = null; // Innitialise the returned variable in case of failure
    foreach($array as $val) { // For every array value, unless stopped
        $result = $val; // Set result to current array value
        if($value <= $result) break; // Stop foreach loop if value is less than or equal to result
    }
    return $result; // Return last result from Foreach loop
}

Widget(9000);

?>

希望这些评论有用...我比平时提供了更多细节...