bcadd
(PHP 4, PHP 5)
bcadd — Add two arbitrary precision numbers
Description
string bcadd
( string
$left_operand
, string $right_operand
[, int $scale
] )
Sums left_operand and
right_operand.
Parameters
-
left_operand -
The left operand, as a string.
-
right_operand -
The right operand, as a string.
-
scale -
This optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global default scale for all functions by using bcscale().
Return Values
The sum of the two operands, as a string.
Examples
Example #1 bcadd() example
<?php
$a = '1.234';
$b = '5';
echo bcadd($a, $b); // 6
echo bcadd($a, $b, 4); // 6.2340
?>
Коментарии
Be aware:
$exp1 = "1E5";
$exp2 = "2E4";
$ans1 = bcadd((float)$exp1, (float)$exp2, 3);
$ans2 = bcadd((int)$exp1, (int)$exp2, 3);
$ans3 = bcadd($exp1, $exp2, 3);
echo "1: $exp1 + $exp2 = $ans1\r\n";
echo "2: $exp1 + $exp2 = $ans2\r\n";
echo "3: $exp1 + $exp2 = $ans3\r\n";
1: 1E5 + 2E4 = 120000.000
2: 1E5 + 2E4 = 3.000
3: 1E5 + 2E4 = 0.000
I made this to add an unlimited size of numbers together..
This could be useful for those without the BCMath extension.
It allows decimals, and optional $Scale parameter. If $Scale isn't specified, then it'll automatically adjust to show the correct number of decimals.
<?php
function Add($Num1,$Num2,$Scale=null) {
// check if they're valid positive numbers, extract the whole numbers and decimals
if(!preg_match("/^\+?(\d+)(\.\d+)?$/",$Num1,$Tmp1)||
!preg_match("/^\+?(\d+)(\.\d+)?$/",$Num2,$Tmp2)) return('0');
// this is where the result is stored
$Output=array();
// remove ending zeroes from decimals and remove point
$Dec1=isset($Tmp1[2])?rtrim(substr($Tmp1[2],1),'0'):'';
$Dec2=isset($Tmp2[2])?rtrim(substr($Tmp2[2],1),'0'):'';
// calculate the longest length of decimals
$DLen=max(strlen($Dec1),strlen($Dec2));
// if $Scale is null, automatically set it to the amount of decimal places for accuracy
if($Scale==null) $Scale=$DLen;
// remove leading zeroes and reverse the whole numbers, then append padded decimals on the end
$Num1=strrev(ltrim($Tmp1[1],'0').str_pad($Dec1,$DLen,'0'));
$Num2=strrev(ltrim($Tmp2[1],'0').str_pad($Dec2,$DLen,'0'));
// calculate the longest length we need to process
$MLen=max(strlen($Num1),strlen($Num2));
// pad the two numbers so they are of equal length (both equal to $MLen)
$Num1=str_pad($Num1,$MLen,'0');
$Num2=str_pad($Num2,$MLen,'0');
// process each digit, keep the ones, carry the tens (remainders)
for($i=0;$i<$MLen;$i++) {
$Sum=((int)$Num1{$i}+(int)$Num2{$i});
if(isset($Output[$i])) $Sum+=$Output[$i];
$Output[$i]=$Sum%10;
if($Sum>9) $Output[$i+1]=1;
}
// convert the array to string and reverse it
$Output=strrev(implode($Output));
// substring the decimal digits from the result, pad if necessary (if $Scale > amount of actual decimals)
// next, since actual zero values can cause a problem with the substring values, if so, just simply give '0'
// next, append the decimal value, if $Scale is defined, and return result
$Decimal=str_pad(substr($Output,-$DLen,$Scale),$Scale,'0');
$Output=(($MLen-$DLen<1)?'0':substr($Output,0,-$DLen));
$Output.=(($Scale>0)?".{$Decimal}":'');
return($Output);
}
$A="5650175242.508133742";
$B="308437806.831153821478770";
printf(" Add(%s,%s);\r\n// %s\r\n\r\n",$A,$B, Add($A,$B));
printf("BCAdd(%s,%s);\r\n// %s\r\n\r\n",$A,$B,BCAdd($A,$B));
/*
This will produce the following..
Add(5650175242.508133742,308437806.831153821478770);
// 5958613049.33928756347877
BCAdd(5650175242.508133742,308437806.831153821478770);
// 5958613049
*/
?>
It was a fun experience making, and thought I'd share it.
Enjoy,
Nitrogen.