Ceiling in a sorted array

04 Jun 2019

int ceilSearch(int arr[], int low, int high, int x)
{
	int mid;

	if (x <= arr[low])
	{
		return low;
	}

	if (x > arr[high])
	{
		return -1;
	}

	mid = (low + high) / 2; /* low + (high - low)/2 */

	if (arr[mid] == x)
	{
		return mid;
	}
	else if (arr[mid] < x)
	{
		if (mid + 1 <= high && x <= arr[mid + 1])
		{
			return mid + 1;
		}
		else
		{
			return ceilSearch(arr, mid + 1, high, x);
		}
	}
	else
	{
		if (mid - 1 >= low && x > arr[mid - 1])
		{
			return mid;
		}
		else
		{
			return ceilSearch(arr, low, mid - 1, x);
		}
	}
}