Convert a big integer to a full string in PHP

Question

I\'ve been searching for a while now, but what I can find is not what I search for. I need to convert an integer value, that may be very huge, to a string. Sounds e

Answer 1

The integer number you like to express:

$var = 10000000000000000000000000;

is not available on your system. It's too large and therefore PHP converts it into a float which will change the number (32 bit system example):

       10000000000000000905969664

Common limits are:

 yours :  10 000 000 000 000 000 000 000 000
 32 bit:                       2 147 483 648
 64 bit:           9 223 372 036 854 775 808

The change of the value is called floating point precision, the PHP manual about integers will tell you about the integer limit and the floats page about floating point precision (see the big red warning). Depending on which system you are, you can compile PHP with the ranges your application needs or you must use another datatype, for example with the gmp library which is able to pick strings as integer numbers and handle them.

The following example shows just output, but you can do multiplications etc.:

$r = gmp_init('10000000000000000000000000');
echo gmp_strval($r);

Hope this is helpful.