bcscale

Description

bool bcscale ( int scale )

This function sets the default scale parameter for all subsequent bc math functions that do not explicitly specify a scale parameter. 如果成功则返回 TRUE，失败则返回 FALSE。

范例

例子 1. bcscale() example


<?php

// default scale : 3
bcscale(3);
echo bcdiv('105', '6.55957'); // 16.007

// this is the same without bcscale()
echo bcdiv('105', '6.55957', 3); // 16.007

?>

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invincible at limitedintelligence dot com
08-Feb-2006 07:50


If you don't set the default scale, be careful when you're chaining together several BC math functions - since by default, these functions will round off your values, losing accuracy very quickly:



<?php

$a = 1.234

$b = 2.345

$c = 7.890



$ab = bcmul($a,$b);           // 2

$abc = bcmul($ab,$c);



echo $abc;                 // 15

?>



... compare with the answer you get when you use more decimal places:



<?php

$a = 1.234

$b = 2.345

$c = 7.890



bcscale(15);

$ab = bcmul($a,$b);           // 2.893730

$abc = bcmul($ab,$c);



echo $abc;                 // 22.83152970

?>

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