Question

考虑下面给出的大计算

echo  999999*999999999;

这会返回9.99998999E+14

有没有办法得到整数999998999000001而不是指数形式？

请帮忙。提前谢谢。

Answer 1

而不是回声，请执行以下操作：use sprintf

$a = 999999*999999999;
$myvar = sprintf('%.0f', $a);

Answer 2

使用GNU Multiple Precision扩展程序：

http://php.net/manual/en/book.gmp.php

Answer 3

不，PHP会将整数，超过24亿的值整数到浮点数，如果你有64位系统，PHP可能会更进一步，但你所要求的根本不可能。

整数的大小取决于平台，尽管是最大值大约20亿是通常的值（32位签名）。 PHP 不支持无符号整数。可以确定整数大小使用常量PHP_INT_SIZE，并使用常量的最大值自PHP 4.4.0和PHP 5.0.5以来的PHP_INT_MAX。

LINK

Answer 4

<?php 
$no = 999999*999999999;
echo sprintf('%.0f', $no);
?>

Answer 5

我想自己编写，但是在查看php文档时我找到了一个就绪函数。它将整数视为字符串，如GMP或BCMath。通过这种方式，您的尺寸不受限制。

此处提供以下功能：http://www.php.net/manual/en/function.bcmul.php

function Mul($Num1='0',$Num2='0') {
  // check if they're both plain numbers
  if(!preg_match("/^\d+$/",$Num1)||!preg_match("/^\d+$/",$Num2)) return(0);

  // remove zeroes from beginning of numbers
  for($i=0;$i<strlen($Num1);$i++) if(@$Num1{$i}!='0') {$Num1=substr($Num1,$i);break;}
  for($i=0;$i<strlen($Num2);$i++) if(@$Num2{$i}!='0') {$Num2=substr($Num2,$i);break;}

  // get both number lengths
  $Len1=strlen($Num1);
  $Len2=strlen($Num2);

  // $Rema is for storing the calculated numbers and $Rema2 is for carrying the remainders
  $Rema=$Rema2=array();

  // we start by making a $Len1 by $Len2 table (array)
  for($y=$i=0;$y<$Len1;$y++)
    for($x=0;$x<$Len2;$x++)
      // we use the classic lattice method for calculating the multiplication..
      // this will multiply each number in $Num1 with each number in $Num2 and store it accordingly
      @$Rema[$i++%$Len2].=sprintf('%02d',(int)$Num1{$y}*(int)$Num2{$x});

  // cycle through each stored number
  for($y=0;$y<$Len2;$y++)
    for($x=0;$x<$Len1*2;$x++)
      // add up the numbers in the diagonal fashion the lattice method uses
      @$Rema2[Floor(($x-1)/2)+1+$y]+=(int)$Rema[$y]{$x};

  // reverse the results around
  $Rema2=array_reverse($Rema2);

  // cycle through all the results again
  for($i=0;$i<count($Rema2);$i++) {
    // reverse this item, split, keep the first digit, spread the other digits down the array
    $Rema3=str_split(strrev($Rema2[$i]));
    for($o=0;$o<count($Rema3);$o++)
      if($o==0) @$Rema2[$i+$o]=$Rema3[$o];
      else @$Rema2[$i+$o]+=$Rema3[$o];
  }
  // implode $Rema2 so it's a string and reverse it, this is the result!
  $Rema2=strrev(implode($Rema2));

  // just to make sure, we delete the zeros from the beginning of the result and return
  while(strlen($Rema2)>1&&$Rema2{0}=='0') $Rema2=substr($Rema2,1);

  return($Rema2);
}

echo Mul('999999', '999999999');

比较

的结果

$a = 99999999*99999999999;
echo sprintf('%.0f', $a);

和

echo Mul('99999999', '99999999999');

用PHP计算

5 个答案: