<?php

// Algorithms
// www.scriptol.com
// Recursive binary search algorithm  on an array of strings.
// Returns the index of an element in the array,
// or -1 if the string can not be found.
// The string must be sorted in ascending order in the array.
// The array is a global variable, that optimizes speed.
// The move is performed by the starting and ending indices.
$A=array("alpha","ariana","beta","bridget","delphina","delta","omega","orwell","pi","ro","rosana");
$size=count($A);
$val="";
function binarySearch($value,$starting,$ending)
{
   if($ending<$starting)
   {
      return -1;
   }
   $mid=intVal(($starting+$ending)/2);
   global $A;
   $result=intVal(strcmp($value,$A[$mid]));
   
   if($result===0)
   {
      return $mid;
   }
   else
   {
      if($result<0)
      {
         $ending=$mid-1;
      }
   else
   {
      if($result>0)
      {
         $starting=$mid+1;
      }
   }}
   return binarySearch($value,$starting,$ending);
}

print_r($A);

echo "Give a word to search:";
$fp=fopen("php://stdin","r");
$val=rtrim(fgets($fp,65536));
fclose($fp);

$y=binarySearch($val,0,count($A)-1);
if($y>=0)
{
   echo $val, " ", "is at position", " ", $y, "\n";
}
else
{
   echo $val, " ", "not found in the array...", "\n";
}


?>