统计数字问题

我是小学生想用QBASIC

CLS
DIM j, n, num As LONG
DIM k As Integer, a(9) AS INTEGER, i AS INTEGER

INPUT N

FOR j = 1 TO n
num = j
k = LEN(CSTR(num))
FOR i = 1 TO k
SELECT CASE num MOD 10
CASE 0: a(0) = a(0) + 1
CASE 1: a(1) = a(1) + 1
CASE 2: a(2) = a(2) + 1
CASE 3: a(3) = a(3) + 1
CASE 4: a(4) = a(4) + 1
CASE 5: a(5) = a(5) + 1
CASE 6: a(6) = a(6) + 1
CASE 7: a(7) = a(7) + 1
CASE 8: a(8) = a(8) + 1
CASE 9: a(9) = a(9) + 1
END SELECT
num = INT(num / 10)
NEXT i
NEXT j
FOR i = 0 TO 9
PRINT "数字" ,i,"的个数为: " ,a(i)
Next i