PHP四舍五入到5的前一个倍数

Question

Expected function signature:

function roundToPreviousMultipleWithDecimal(float $number, int $x = 5): float;

• 8.4 => 8.0
• 8.6 => 8.5
• 8.9 => 8.5
• 9.0 => 9.0

Answer 1

an easy solution, floor the double number and divide by two... 2 cents ;)

<?php

function roundToPreviousMultipleWithDecimal(float $number){

        return $specificRound = floor($number * 2) / 2;
}

$a = 8.4;
$b = 8.6;
$c = 8.9;
$d = 9.0;

echo roundToPreviousMultipleWithDecimal($a) ."<br />";
echo roundToPreviousMultipleWithDecimal($b) ."<br />";
echo roundToPreviousMultipleWithDecimal($c) ."<br />";
echo roundToPreviousMultipleWithDecimal($d) ."<br />";