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 copyrightfunction 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/>";}