Precision arithmetics

PHP
1

How can i get precise number values out of PHP
like when i calculate this on a calculator or spread sheet, google… 7.33 * 14 = 102.62

but when i create a little function in PHP to do the same, i get this $102.68
any one else come across this problem.

any help would be great.


function calculate_intrest_charge($dailyrate)
{
      $result = ($dailyrate * 14);
      return $result;
	
}

function money_form($cash)
{
      return "$" . number_format($cash, 2, '.', ' ,');

}

$ic = calculate_intrest_charge(7.3343435512329);
echo money_form($ic); 

/* why does PHP produce this value =   
$102.68 when it should be $102.62  */
2

You should use BCMath Arbitrary Precision Mathematics extension or [url=http://lv.php.net/manual/en/book.gmp.php]GNU Multiple Precision extension.

3

i tryed to use it the GMP extensions with the demo code


$abs1 = gmp_abs("274982683358");
$abs2 = gmp_abs("-274982683358");
echo gmp_strval($abs1) . "\
";
echo gmp_strval($abs2) . "\
";

[B]

all i get is

Fatal error: Call to undefined function gmp_abs() in G:\xampplite\ est.php on line 120
[/B]

How do i get PHP to identify it…frustrating the hell out of me…all this should be built in man…

4

You might need to enable it in your php.ini file. Open it and search for gmp.dll

5

7.3343435512329 * 14 = 102.6808097

I don’t understand why you want PHP to return 102.62 ? Or am I missing something?

6

Didn 't even check the correctness of calculations :smiley:

7 

echo money_form(bcmul("07.33","14")); /* i came up with this $102.62 */

but i want inputs to be more human readable, simple as using a daam calculator.

will installing GMP extensions solve all this…

8

forget it… i solved it myself…

9

Care to share how? :slight_smile:

10 

	function calculate_dailyrate($intrest)
	{		
		$result = bcdiv($intrest,365);
		return round($result,2);
	}

	function money_form($cash)
	{
		return "$" .  number_format($cash, 2, '.', ' ,');
	}

echo money_form(calculate_dailyrate(2677.04))	/* Outputs: $7.33 */;

it does what i want for now anyway, for clean cut presentation outputs i used bcdiv() round() functions…