Java program to perform binary search

Java program for binary search: This code implements the binary search algorithm. Binary search compares the target value to the middle element of the array. It works only on a sorted set of elements. To use binary search on a collection, the collection must first be sorted.

import java.util.Scanner;
class BinarySearch
{
  public static void main(String args[])
  {
    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 + " isn't present in the list.\n");
  }
}

Program Output:

Enter number of Elements:
5
Enter 5 integers:
24
67
45
60
27
Enter value to find:
67
67 found at location 2

I hope this post helps you to understand Binary Search and its implementation in Java programming language.

Keep coding 🙂