Binary Search.c

  //write a recursion function for 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(void)
{
   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);
    if(result == -1)
        printf("Element is not present in array");
    printf("Element is present at index %d", result);
   return 0;
}