Ceil search in sorted array

/* Function to get index of 
       ceiling of x in arr[low..high]*/
    static int ceilSearch(int arr[], int low, int high, int x)
    {
      int mid;    
       
      /* If x is smaller than or equal to the 
         first element, then return the first element */
      if(x <= arr[low])
        return low; 
      
      /* If x is greater than the last 
         element, then return -1 */
      if(x > arr[high])
        return -1;  
      
      /* get the index of middle element 
         of arr[low..high]*/
      mid = (low + high)/2;  /* low + (high - low)/2 */
      
      /* If x is same as middle element, 
         then return mid */
      if(arr[mid] == x)
        return mid;
          
      /* If x is greater than arr[mid], then 
         either arr[mid + 1] is ceiling of x or 
         ceiling lies in arr[mid+1...high] */
      else if(arr[mid] < x)
      {
        if(mid + 1 <= high && x <= arr[mid+1])
          return mid + 1;
        else
          return ceilSearch(arr, mid+1, high, x);
      }
      
      /* If x is smaller than arr[mid], 
         then either arr[mid] is ceiling of x 
         or ceiling lies in arr[mid-1...high] */  
      else
      {
        if(mid - 1 >= low && x > arr[mid-1])
          return mid;
        else   
          return ceilSearch(arr, low, mid - 1, x);
      }
    }