php实现将任意进制数转换成10进制的方法

本文实例讲述了php实现将任意进制数转换成10进制的方法。分享给大家供大家参考。具体如下：

php将任意进制的数转换成10进制，例如8进制转换成10进制，16进制转换成10进制

    <?php
    # Show the steps involved in converting a number 
    # from any base (like octal or hex) to base 10
    # See below for examples, instructions and copyright
    function show_convert_to_base_10 ($number, $base)
    {
     // If the number contains a decimal component
     if (strstr ($number, '.'))
     {
      // Get the integer and decimal components
      list ($integer, $decimal) = explode ('.', $number);
     }
     else
     {
      // The number is an integer
      $integer = $number;
     }
      print "<b>Convert the base $base number $number to a
      base 10 number:</b><blockquote>";
      print "Convert the integer component ($integer) of the
       number:<blockquote>";
     // Compute the value of the integer component
     // Loop through the integer digit by digit
     // Reverse the number for easier handling
     $integer = strrev ($integer);
     $length = strlen ($integer);
     for ($pos = 0; $pos < $length; ++$pos)
     {
      /*
       PHP lets you treat strings and numbers like arrays
       Specify an offset and get the character at that
       position
      */
       $digit = $integer[$pos];
      // Handle character values for digits
      // (for bases greater than 10)
      if (eregi ('[a-z]', $digit))
      {
       $digit_value =
         (ord (strtolower ($digit))
         - ord ('a')) + 10;
        $digit = "$digit ($digit_value)";
      }
      else
      {
       $digit_value = $digit;
      }
      // Multiply the current digit by the radix
      // raised to the power of the current position
      $result = $digit_value * pow ($base, $pos);
       print "Multiply the value of the digit at position
        $pos by the value of the radix ($base) raised
        to the power of the position ($pos):<br/>";
       print "$digit * $base<sup>$pos</sup> = $result
        <br/><br/>";
       $sums[] = $result;
     }
     print '</blockquote>';
     if (isset ($decimal))
     {
       print "Convert the decimal component (0.$decimal)
       of the number:<blockquote>";
      // Pad the number with a leading 0 so that we can
      // start at position 1
      $decimal = '0'.$decimal;
      $length = strlen ($decimal);
       for ($pos = 1; $pos < $length; ++$pos) {
       $digit = $decimal[$pos];
       // Handle character values for digits
       // (for bases greater than 10)
       if (eregi ('[a-z]', $digit))
       {
         $digit_value =
         (ord (strtolower ($digit))
         - ord ('a')) + 10;
          $digit = "$digit ($digit_value)";
       }
       else
       {
         $digit_value = $digit;
       }
       // Multiply the current digit by the radix
       // raised to the power of the current position
       $result = $digit_value * pow (1/$base, $pos);
        print "Multiply the value of the digit at
        position $pos by the value of the 1/radix
        ($base) raised to the power of the position
        ($pos):<br/>";
        print "$digit * 1/$base<sup>$pos</sup> =
        $result<br/><br/>";
        $sums[] = $result;
      }
      print '</blockquote>';
     }
     $sums = implode (' + ', $sums);
     eval ("\$base_10_value = $sums;");
      print "</blockquote>The value of the base $base number
      $number in base 10 is $base_10_value. <br/>";
      print "This number is derived from the sum of the values
      of the previous operations ($sums). <br/> <br/>";
    }

希望本文所述对大家的php程序设计有所帮助。