RecursiveBinarySearch.java

public class RecursiveBinarySearch {
    public static int recursiveBinarySearch(int arr[], int firstElement, int lastElement, int elementToSearch) {

        // termination condition
        if (lastElement >= firstElement) {
            int mid = firstElement + (lastElement - firstElement) / 2;
    
            // if the middle element is our goal element, return its index
            if (arr[mid] == elementToSearch)
                return mid;
    
            // if the middle element is bigger than the goal element
            // recursively call the method with narrowed data
            if (arr[mid] > elementToSearch)
                return recursiveBinarySearch(arr, firstElement, mid - 1, elementToSearch);
    
            // else, recursively call the method with narrowed data
            return recursiveBinarySearch(arr, mid + 1, lastElement, elementToSearch);
        }
    
        return -1;
    }
    public static void main(String[] args) {
        int index = recursiveBinarySearch(new int[]{3, 22, 27, 47, 57, 67, 89, 91, 95, 99}, 0, 10, 89);
        System.out.print(89+" found at index "+ index);   
    }
}