Adding .3 to .-3 in a for loop giving me a number in scientific notation and not 0 in PHP. Why?

Question

I have this PHP code below:

$value = -.9;
for ($i = 0; $i <= 6; $i++) {
    echo "value = $value , ";
    $value += .3;
}

Output:

value = -0.9 , value = -0.6 , value = -0.3 , value = -1.11022302463E-16 , value = 0.3 , value = 0.6 , value = 0.9 ,

Why am I getting -1.11022302463E-16 and not 0? And what can I do to correct the problem? Thanks again.

because `0.3` and the like cannot be presented exactly as floating point numbers. it's 0.299999999999234524234234 or whatever interally. — Marc B, May 23 '14 at 17:17

score 1 · Accepted Answer · answered May 23 '14 at 17:23

1

try this

echo 'value = ' . number_format($value,0,'','').', ';

answered May 23 '14 at 17:23

MH2K9

1 Answers1