Binary Search

package org.interview.test;

import java.util.Arrays;
import java.util.Scanner;

public class BinarySearch {

public static void main (String [] args) throws Exception {
binarySearch();

binarySearch02();
}



public static void binarySearch02(){


int c, first, last, middle, n, search, array[];
 
   Scanner in = new Scanner(System.in);
   System.out.println("Enter number of elements");
   n = in.nextInt(); 
   array = new int[n];
 
   System.out.println("Enter " + n + " integers");
 
 
   for (c = 0; c < n; c++)
     array[c] = in.nextInt();
 
   System.out.println("Enter value to find");
   search = in.nextInt();
 
   first  = 0;
   last   = n - 1;
   middle = (first + last)/2;
 
   while( first <= last )
   {
     if ( array[middle] < search )
       first = middle + 1;    
     else if ( array[middle] == search ) 
     {
       System.out.println(search + " found at location " + (middle + 1) + ".");
       break;
     }
     else
        last = middle - 1;
 
     middle = (first + last)/2;
  }
  if ( first > last )
     System.out.println(search + " is not present in the list.\n");
  
  
}

/**
* binarySearch method returns the location if a match occurs otherwise -(x+1) 
* where x is the no. of elements in the array, For example in the second case 
* above when p is not present in characters array the returned value will be -6.
*/
public static void binarySearch (){
char characters[] = { 'a', 'b', 'c', 'd', 'e' };
 
   System.out.println(Arrays.binarySearch(characters, 'a'));
   System.out.println(Arrays.binarySearch(characters, 'c'));
   System.out.println(Arrays.binarySearch(characters, 'p'));
}
}