PHP Manual: Multiplies an arbitrary precision number

Description

public BcMath\Number BcMath\Number::mul(BcMath\Numberstringint $num, intnull $scale = null)

Multiplies $this by num.

Parameters

num: The multiplier.
scale: BcMath\Number::scale explicitly specified for calculation results. If null, the BcMath\Number::scale of the calculation result will be set automatically.

Return Values

Returns the result of multiplication as a new BcMath\Number object.

When the BcMath\Number::scale of the result object is automatically set, the sum of the BcMath\Number::scales of the two values used for multiplication is used.

That is, if the BcMath\Number::scales of two values are 2 and 5 respectively, the BcMath\Number::scale of the result will be 7.

Errors/Exceptions

This method throws a ValueError in the following cases:

num is string and not a well-formed BCMath numeric string
scale is outside the valid range
BcMath\Number::scale of the result object is outside the valid range

Examples

Example #1 BcMath\Number::mul example when scale is not specified

<?php
$number = new BcMath\Number('1.234');

$ret1 = $number->mul(new BcMath\Number('2.3456'));
$ret2 = $number->mul('-3.4');
$ret3 = $number->mul(7);

var_dump($number, $ret1, $ret2, $ret3);
?>

The above example will output:

object(BcMath\Number)#1 (2) {
  ["value"]=>
  string(5) "1.234"
  ["scale"]=>
  int(3)
}
object(BcMath\Number)#3 (2) {
  ["value"]=>
  string(9) "2.8944704"
  ["scale"]=>
  int(7)
}
object(BcMath\Number)#2 (2) {
  ["value"]=>
  string(7) "-4.1956"
  ["scale"]=>
  int(4)
}
object(BcMath\Number)#4 (2) {
  ["value"]=>
  string(5) "8.638"
  ["scale"]=>
  int(3)
}

Example #2 BcMath\Number::mul example of explicitly specifying scale

<?php
$number = new BcMath\Number('1.234');

$ret1 = $number->mul(new BcMath\Number('2.3456'), 1);
$ret2 = $number->mul('-3.4', 10);
$ret3 = $number->mul(7, 0);

var_dump($number, $ret1, $ret2, $ret3);
?>