For more information, please refer to: ISBN-wikipedia, here's a brief description of what the ISBN code is:
ISBN (International Standard book NUMBER,ISBN; intended pronunciation is-ben), is the code of international Books or independent publications (in addition to periodical publications). Publishers can clearly identify all non-periodical books through the ISBN. One ISBN only one or a corresponding publication corresponds to it. The new version will not be published without a new international standard book number if there is no change in content on the basis of the original version. When the paperback is converted to hardback, the corresponding ISBN number should also be withdrawn.
Usually we can see the ISBN code has 10-bit and 13-bit, of which 10-bit ISBN has been discontinued since January 2007, the current new book ISBN code is 13 bits. Considering a rigorous book management process to take into account a variety of issues, because the 10-bit ISBN code Books still have a huge amount of storage, so to verify the correctness of the book ISBN code, you must consider both 10-bit and 13-bit situation. From Wikipedia can be learned that the last one is the ISBN code, in fact, to verify the correct ISBN code, is to calculate the ISBN check code, see if it matches the last one. The checksum here is only verifying that the ISBN is legitimate on the composition, and does not verify that the ISBN is a published book. The following is an ISBN code verification algorithm provided by Wikipedia:
The calculation method of the check code (10 yards)
Assuming some ISBN number the first 9 bits are: 7-309-04547
Calculate weighted and s:s = 7X10+3X9+0X8+9X7+0X6+4X5+5X4+4X3+7X2 = 226
Calculates the remainder of the s÷11 m:m = 226 MoD 11 = 6
Calculate the difference between 11–m n = 11? 6 = 5
If n = 10, the check code is the letter "X"
If n = 11, the check code is the number "0"
If n is a different number, the checksum is the number n
Therefore, the check code of this book is 5; If the user provides an ISBN code of 7-309-04547-6, then the checksum fails
The calculation method of the check code (13 yards)
Assuming some ISBN number the first 12 bits are: 978-986-181-728
Calculated weights and s:s = (9x1) + (7X3) + (8x1) + (9X3) + (8x1) + (6x3) + (1x1) + (8x3) + (1x1) + (7X3) + (2x1) + (8x3) = 164
Calculates the remainder of the s÷10 m:m = 164 mod 10 = 4
Calculate the difference between 10–m n = 10? 4 = 6
If n = 10, the check code is the number "0"
If n is a different number, the checksum is the number n
So, the check code for this book is 6. Complete ISBN number for ISBN 978-986-181-728-6
Well, background knowledge introduced to this, below I write the ISBN code check function (PHP version), if necessary, can be used directly:
Copy the Code code as follows:
function Isbn_sum ($ISBN, $len)
{
/*
* This function is used to calculate the ISBN weighting and
* Parameter Description:
* $ISBN: ISBN code
* $len: ISBN code length
*/
$sum = 0;
if ($len = = 10)
{
for ($i = 0; $i < $len-1; $i + +)
{
$sum = $sum + (int) $ISBN [$i] * ($len-$i);
}
}
ElseIf ($len = = 13)
{
for ($i = 0; $i < $len-1; $i + +)
{
if ($i% 2 = = 0)
$sum = $sum + (int) $ISBN [$i];
Else
$sum = $sum + (int) $ISBN [$i] * 3;
}
}
return $sum;
}
function Isbn_compute ($ISBN, $len)
{
/*
* This function is used to calculate the ISBN check digit
* Parameter Description:
* $ISBN: ISBN code
* $len: ISBN code length
*/
if ($len = = 10)
{
$digit = 11-isbn_sum ($ISBN, $len)% 11;
if ($digit = = 10)
$RC = ' X ';
else if ($digit = = 11)
$RC = ' 0 ';
Else
$RC = (string) $digit;
}
else if ($len = = 13)
{
$digit = 10-isbn_sum ($ISBN, $len)% 10;
if ($digit = = 10)
$RC = ' 0 ';
Else
$RC = (string) $digit;
}
return $RC;
}
function Is_isbn ($ISBN)
{
/*
* This function is used to determine whether the ISBN number
* Parameter Description:
* $ISBN: ISBN code
*/
$len = strlen ($ISBN);
if ($len!=10 && $len!=13)
return 0;
$RC = Isbn_compute ($ISBN, $len);
if ($ISBN [$len-1]! = $RC)/* ISBN mantissa does not match the calculated check code */
return 0;
Else
return 1;
}
Once the function is written, it can be called directly, and here is an example of the invocation:
Copy the Code code as follows:
In addition, I wrote an online verification of the ISBN tool, using the tool can check the validity of the ISBN code online, you can click the following link to use: ISBN Code Online verification Tool
The above describes the Gisele Bundchen PHP Check ISBN code function code, including the Gisele Bundchen aspects of the content, I hope that the PHP tutorial interested in a friend helpful.
