MS SQL: Update trigger to update a value based on another updated value

DECLARE @days TABLE(id INT IDENTITY(1,1), NumOfDays INT NULL, dueDate DATETIME) 

INSERT INTO @days (dueDate)
SELECT '2013-06-01'
UNION ALL SELECT '2013-06-07'
UNION ALL SELECT '2013-06-10'
UNION ALL SELECT '2013-06-15'
UNION ALL SELECT '2013-06-19'
UNION ALL SELECT '2013-06-30'
UNION ALL SELECT '2013-07-01'
UNION ALL SELECT '2013-07-05'
UNION ALL SELECT '2013-07-15'
UNION ALL SELECT '2013-07-24'

UPDATE dst
	SET NumOfDays = DATEDIFF(dd, dst.dueDate, src.CurrDate)
FROM @days AS dst INNER JOIN (
	SELECT id-1 AS id, dueDate AS CurrDate
	FROM @days
	) AS src ON dst.id = src.id

SELECT id, NumOfDays, CONVERT(NVARCHAR(10),dueDate,121) AS dueDate
FROM @days

DECLARE @days TABLE(id INT IDENTITY(1,1), NumOfDays INT, dueDate DATETIME NULL) 

INSERT INTO @days (NumOfDays, dueDate)
SELECT 6, '2013-06-01'
UNION ALL SELECT 3, NULL
UNION ALL SELECT 5, NULL
UNION ALL SELECT 4, NULL
UNION ALL SELECT 11, NULL
UNION ALL SELECT 1, NULL
UNION ALL SELECT 4, NULL
UNION ALL SELECT 10, NULL
UNION ALL SELECT 9, NULL


;WITH dates AS
(
	SELECT id, NumOfDays, dueDate, DATEADD(dd,NumOfDays,dueDate) AS newDate
	FROM @days
	WHERE (dueDate IS NOT NULL) AND (NumOfDays IS NOT NULL)
	UNION ALL
	SELECT t1.id, t1.NumOfDays, t2.newDate AS dueDate, DATEADD(dd,t1.NumOfDays,t2.newDate) AS newDate
	FROM @days AS t1 INNER JOIN dates AS t2 ON t1.id-1 = t2.id
	WHERE (t1.dueDate IS NULL) AND (t1.NumOfDays IS NOT NULL)
)
UPDATE dst
	SET dueDate = src.dueDate
FROM @days AS dst INNER JOIN dates AS src ON dst.id = src.id

SELECT id, NumOfDays, CONVERT(NVARCHAR(10),dueDate,121) AS dueDate
FROM @days

1	6	2013-06-01
2	3	2013-06-07
3	5	2013-06-10
4	4	2013-06-15
5	11	2013-06-19
6	1	2013-06-30
7	4	2013-07-01
8	10	2013-07-05
9	9	2013-07-15