php ROUNDDOWN双精度版本控制

<?php
// 整数舍入示例
$number = 3.7;
$roundedDownInteger = floor($number);
echo "ROUNDDOWN of $number is $roundedDownInteger\n"; // 输出: ROUNDDOWN of 3.7 is 3

// 小数位舍入示例
$number = 3.745;
$decimalPlaces = 2;
$roundedDownDecimal = floor($number * pow(10, $decimalPlaces)) / pow(10, $decimalPlaces);
echo "ROUNDDOWN of $number to $decimalPlaces decimal places is $roundedDownDecimal\n"; // 输出: ROUNDDOWN of 3.745 to 2 decimal places is 3.74
?>

<?php
require_once 'vendor/autoload.php'; // 确保已安装 bcmath 扩展

$number = 3.745;
$decimalPlaces = 2;
$roundedDownDecimal = bcdiv(bcadd(bcmul((string)$number, strval(pow(10, $decimalPlaces))), '0'), strval(pow(10, $decimalPlaces)));
echo "ROUNDDOWN of $number to $decimalPlaces decimal places is $roundedDownDecimal\n"; // 输出: ROUNDDOWN of 3.745 to 2 decimal places is 3.74
?>

<?php
$number = -3.7;
$roundedDownInteger = floor($number);
echo "ROUNDDOWN of $number is $roundedDownInteger\n"; // 输出: ROUNDDOWN of -3.7 is -4

// 如果需要向上舍入负数，可以使用 ceil 函数
$roundedUpInteger = ceil($number);
echo "ROUNDUP of $number is $roundedUpInteger\n"; // 输出: ROUNDUP of -3.7 is -3
?>