src/BinarySearch.java

public class BinarySearch {

        public static int binarySearch(int arr[], int low, int high, int key) {
        int mid = (low + high) / 2;

        while (low <= high) {
            if (arr[mid] < key) {
                low = mid + 1;
            } else if (arr[mid] == key) {
                return mid;
            } else {
                high = mid - 1;
            }
            mid = (low + high) / 2;
        }
        if (low > high) {
            return -1;
        }
        return -1;
    }

    public static void main(String[] args) {
        int intArray[] = {7, 8, 9};

        int key = 8;

        if (binarySearch(intArray, 0, 5, key) != -1) {

            System.out.print("searching `");
            System.out.print(key);
            System.out.print("` in the array... it's at index ");
            System.out.println(binarySearch(intArray, 0, 5, key));
            

        } else {

            System.out.println("index not found");

        }
    }

}