Weird output, when number starts with 0

Question

1. script:

$num = \"00445790\";
echo $num;

returns:

00445790

2. script

$num = 00445790;
echo          


        

Answer 1

Integers that start with zero are consider octal. Because octal integers only use numbers from 0 to 8 everything from the 9 on are ignored.

So 00445790 becomes 004457 which is 2351 in decimal.