PHP - 比较2个浮点值时的奇怪结果

Question

I am trying to compare 2 values in PHP.

My logic is:

1. I have a remaining amount (a)
2. I have a amount to be charged (b)
3. I calculate remaining to be by ( a - b )
4. After charge action I get the actual remaining value (c)
5. I compare the value I got in #3 with (c)

Even though the both are similar PHP says they are not equal.

Below given is my code (with filled values)

<?php
$remaining_amount_before_payment = "600";
$remaining_amount_after_payment = (float)$remaining_amount_before_payment - (float)"387.60";
$actual_remaining_amount_after_payment = "212.4";
echo "actual_remaining_amount_after_payment: {$actual_remaining_amount_after_payment} <br><br>";
echo "remaining_amount_after_payment: {$remaining_amount_after_payment} <br><br>";
var_dump( ((float)$actual_remaining_amount_after_payment) == ((float)$remaining_amount_after_payment) );?>

I type cast the values to float, but the var_dump returns FALSE.

Can anybody help me to find out why this is?

I am using PHP 5.6.

Thanks in advance!

Answer 1

Use var_dump(abs(floatval($actual_remaining_amount_after_payment) == floatval($remaining_amount_after_payment)) == 0);