Write a Java program to implement Binary Search.

public class BinarySearch {
    public static void main(String[] args) {
        int c, first, last, middle, n, search_element;

        int array[] = { 100, 200, 300, 400, 500 };
        search_element = 200;

        n = array.length;
        first  = 0;
        last   = n - 1;
        middle = (first + last) / 2;

        while (first <= last) {
            if (array[middle] < search_element)
                first = middle + 1;
            else if (array[middle] == search_element) {
                System.out.println(search_element + " found at location " + (middle + 1) + ".");
                break;
            } else
                last = middle - 1;

            middle = (first + last) / 2;
        }

        if (first > last)
            System.out.println(search_element + " isn't present in the list.\n");
    }
}

200 found at location 2.

Array: [100, 200, 300, 400, 500]   search: 200

Iteration 1:
  first=0, last=4, middle=2 → array[2]=300
  300 > 200 → search left: last = middle-1 = 1

Iteration 2:
  first=0, last=1, middle=0 → array[0]=100
  100 < 200 → search right: first = middle+1 = 1

Iteration 3:
  first=1, last=1, middle=1 → array[1]=200
  200 == 200 → FOUND at index 1 (location 2)