PHP 5.6.0 released

bcadd

(PHP 4, PHP 5)

bcaddAdd two arbitrary precision numbers

Descrierea

string bcadd ( string $left_operand , string $right_operand [, int $scale ] )

Sums left_operand and right_operand.

Parametri

left_operand

The left operand, as a string.

right_operand

The right operand, as a string.

scale

Acest parametru opțional este utilizat pentru a stabili numărul cifrelor după virgulă din rezultat. De asemenea puteți să stabiliți parametrul global scale pentru toate funcțiile utilizând bcscale().

Valorile întoarse

The sum of the two operands, as a string.

Exemple

Example #1 bcadd() example

<?php

$a 
'1.234';
$b '5';

echo 
bcadd($a$b);     // 6
echo bcadd($a$b4);  // 6.2340

?>

Vedeți de asemenea

  • bcsub() - Subtract one arbitrary precision number from another

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User Contributed Notes 2 notes

up
8
Nitrogen
5 years ago
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",$A,$BAdd($A,$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.
up
2
Bo Anders Svensson
9 years ago
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
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