<?php // ----- Functions function Recursion($par,$prev,&$resu,&$nb) { // algorithm : // if length>0 treat first char in a loop, call for the rest // else memorize result and get out recursively if (strlen($par)>0) { switch ($par[0]) { case 0 : $chars=array('0'); break; case 1 : $chars=array('1'); break; case 2 : $chars=array('A','B','C'); break; case 3 : $chars=array('D','E','F'); break; case 4 : $chars=array('G','H','I'); break; // 'I' should be out (confusion with 1) case 5 : $chars=array('J','K','L'); break; case 6 : $chars=array('M','N','O'); break; // 'O' should be out (confusion with 0) case 7 : $chars=array('P','Q','R','S'); break; case 8 : $chars=array('T','U','V'); break; case 9 : $chars=array('W','X','Y','Z'); break; } // switch/case of foreach($chars as $char) { $newst=$prev.$char; Recursion(substr($par,1),$newst,$resu,$nb); } } else { // result found $resu[$nb]=$prev; // substr($resu[$nb-1],0,strlen($resu[$nb-1])-1); $nb++; } } // Recursion Procedure function DoIt($tel) { $resu=array(); $nb=0; Recursion($tel,"",$resu,$nb); return $resu; } // DoIt Array Function // ----- MAIN $numtel='4143'; $result=DoIt($numtel); // $result initialized in DoIt() $nbres=count($result); echo "number $numtel "; echo "$nbres combinations : "; for ($i=0;$i<$nbres;$i++) echo $result[$i].' '; ?>