// C program to implement recursive Binary Search
#include <stdio.h>

// A recursive binary search function. It returns
// location of x in given array arr[l..r] is present,
// otherwise -1
int binarySearch(int arr[], int l, int r, int x) {
  if (r >= l) {
    int mid = l + (r - l) / 2;

    // If the element is present at the middle
    // itself
    if (arr[mid] == x)
      return mid;

    // If element is smaller than mid, then
    // it can only be present in left subarray
    if (arr[mid] > x)
      return binarySearch(arr, l, mid - 1, x);

    // Else the element can only be present
    // in right subarray
    return binarySearch(arr, mid + 1, r, x);
  }

  // We reach here when element is not
  // present in array
  return -1;
}

int main() {
  int arr[] = {2, 3, 4, 10, 40};
  int n = sizeof(arr) / sizeof(arr[0]);
  int x = 10;
  int result = binarySearch(arr, 0, n - 1, x);
  (result == -1) ? printf("Element is not present in array\n")
                 : printf("Element is present at index %d\n", result);
  return 0;
}