Conversion double to int in php

Question

this is a part of my code.I'd like get int value 2040 but the int value is 2039.

$double = 100 * '20.40';
$int = (int)$double;
echo gettype($double)."=$double\n"; //output 2040
echo gettype($int)."=$int\n";      //output 2039

Answer 1

$double = 100 * 20.40;
$int = (int)round($double);

echo gettype($double)."=$double\n"; //output double=2040 
echo gettype($int)."=$int\n"; //output integer=2040