// binarySearch.java
// demonstrates recursive binary search
// to run this program: C>java BinarySearchApp
////////////////////////////////////////////////////////////////
class ordArray
{
   private long[] a;                 // ref to array a
   private int nElems;               // number of data items

   public ordArray(int max)          // constructor
   {
      a = new long[max];             // create array
      nElems = 0;
   }

   //-----------------------------------------------------------
   public int size()
   { 
      return nElems; 
   }

   //-----------------------------------------------------------
   public int find(long searchKey)
   {
      return recFind(searchKey, 0, nElems-1);
   }

   //-----------------------------------------------------------
   private int recFind(long searchKey, int lowerBound,
                                       int upperBound)
   {
      int curIn;

      curIn = (lowerBound + upperBound ) / 2;

      if(a[curIn]==searchKey)
         return curIn;              // found it

      else if(lowerBound > upperBound)
         return nElems;             // can't find it

      else                          // divide range
      {
         if(a[curIn] < searchKey)   // it's in upper half

            return recFind(searchKey, curIn+1, upperBound);

         else                       // it's in lower half

            return recFind(searchKey, lowerBound, curIn-1);

      }  // end else divide range
   }  // end recFind()

   //-----------------------------------------------------------
   public void insert(long value)    // put element into array
   {
      int j;

      for(j = 0; j < nElems; j++)        // find where it goes
         if(a[j] > value)            // (linear search)
            break;

      for(int k = nElems; k > j; k--)    // move bigger ones up
         a[k] = a[k-1];

      a[j] = value;                  // insert it

      nElems++;                      // increment size

   }  // end insert()

   //-----------------------------------------------------------
   public void display()             // displays array contents
   {
      for(int j = 0; j < nElems; j++)       // for each element,
         System.out.print(a[j] + " ");  // display it

      System.out.println("");
   }
   //-----------------------------------------------------------
   }  // end class ordArray

////////////////////////////////////////////////////////////////
class BinarySearchApp
{
   public static void main(String[] args)
   {
      int maxSize = 100;             // array size
      ordArray arr;                  // reference to array
      arr = new ordArray(maxSize);   // create the array

      arr.insert(72);                // insert items
      arr.insert(90);
      arr.insert(45);
      arr.insert(126);
      arr.insert(54);
      arr.insert(99);
      arr.insert(144);
      arr.insert(27);
      arr.insert(135);
      arr.insert(81);
      arr.insert(18);
      arr.insert(108);
      arr.insert(9);
      arr.insert(117);
      arr.insert(63);
      arr.insert(36);

      arr.display();                 // display array

      int searchKey = 27;            // search for item

      if( arr.find(searchKey) != arr.size() )

         System.out.println("Found " + searchKey);

      else
         System.out.println("Can't find " + searchKey);
   }  // end main()
}  // end class BinarySearchApp