RE: [PHP-WIN] Random Code

My guess is that you would need to create the random number and then check that number against a database of saved "random" numbers, to insure uniqueness. If someone would like to critique it, please do I wrote this just for you because I was curious... <?php //holder for the final random thingy $final_rand = ""; //gotta seed the random number generator, although I have no idea what this does srand ((double) microtime() * 10000000); //a little alpha-num array $alpha = array ("A" , "B" , "C" , "D" , "E" , "F" , "G" , "H" , "I" , "J" , "K" , "L" , "M" , "N" , "O" , "P" , "Q" , "R" , "S" , "T" , "U" , "V" , "X" , "Y" , "Z" , "1" , "2" , "3" , "4" , "5" , "6" , "7" , "8" , "9" , "0" ); //get 8 keys for the array $rand_keys = array_rand ($alpha, 8); //cycle through the random keys and build the thingy for ( $i = 0 ; $i <= 7 ; $i++ ) { $final_rand .= $alpha[$rand_keys[$i]]; //throw a dash in there if ( $i == 3 ) { $final_rand .= "-"; } } echo $final_rand; //now you need to check the final value against a database or a comma delimited text file or something where you can check to see if the item has ever been used before and if not, added to the end of the database ?> --------------------- John Asendorf - jasendorf@lcounty.com Web Applications Developer http://www.lcounty.com - NEW FEATURES ADDED DAILY! Licking County, Ohio, USA 740-349-3631 The benefit to the government of replacing all $1 Federal Reserve notes with $1 coins would be $522.2 million per year, according to estimates of the General Accouting Office released on April 7, 2000. > -----Original Message----- > From: Sigurd Magnusson [mailto:phobo@paradise.net.nz] > Sent: Tuesday, January 23, 2001 3:59 AM > To: php-windows@lists.php.net > Subject: [PHP-WIN] Random Code > > > Whats the best way to make a completely random, unique code > in the format "ABCD-1234" where each of the 8 characters can > be alphanumerc; 0-9,A-Z... I thought about generating a 36^4 > number, converting to to base '36', and repeating the > process. What's a good way to ensure the code is not repeated, though? > > Siggy >