Check if ISBN number is legal _php tutorial

Source: Internet
Author: User
[Program Language] PHP [Source] http://px.sklar.com [function description] Check whether the user entered the ISBN number (can be or without a hyphen symbol) is legal. The source code is as follows: <?php/* * Check to see if the entered ISBN is valid and return * True or false depending. * Im not even going to try to claim the copyright for such * a simple thing. Do-you-'ll with it. * 8-) Keith Nunn, kapn@anglican.ca */function CHECKISBN ($ISBN) {$ISBN = Ereg_replace ("[^0-9x]", "", $ISBN); $checkdigit = 11- (* substr ($ISBN 10,0,1) + 9 * substr ($ISBN 10,1,1) + 8 * substr ($ISBN 10,2,1) + 7 * substr ($ISBN 10,3,1) + 6 * SUBSTR ($ isbn10,4,1) + 5 * substr ($ISBN 10,5,1) + 4 * substr ($ISBN 10,6,1) + 3 * substr ($ISBN 10,7,1) + 2 * substr ($ISBN 10,8,1))% 11 ); if ($checkdigit = =) $checkdigit = "X"; if ($checkdigit = =) $checkdigit = 0; if ($checkdigit = = substr ($isbn 10,9,1)) {return true;} else {return false;}} ? >

http://www.bkjia.com/PHPjc/532111.html www.bkjia.com true http://www.bkjia.com/PHPjc/532111.html techarticle [Program Language] PHP [source] http://px.sklar.com [function description] Check whether the user entered the ISBN number (can be with or without the hyphen symbol) is legal. The source code is as follows: ...

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