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PHP PHP Basics Unit Converter Manipulating Numbers

Yu-Che Hung
Yu-Che Hung
Courses Plus Student 10,607 Points

PHP Basic - Variables in PHP - final challenge task what's wrong with my answer?

They said I multiplied the wrong number.


//Place your code below this comment
$integerOne =1;
$integerTwo =2;
$integerOne +=5;
$integerTwo -=1;

$floatOne =1.5;
var_dump($integerOne * $floatOne);


3 Answers

PHP has really nasty floating point precision issues as mentioned here and many other places. This often results in weird results in mathematical operations that result from numbers like 1.5 turning into things like 1.4999999[...] or 1.5000[...]001 internally. In order to solve things like this, it's often necessary to use a function like round() link, floor() link, or something else to artificially create the precision necessary to obtain an expected result.

Jonathan Dewitt
Jonathan Dewitt
8,101 Points

Use echo instead of var_dump.