how to keep previous value in variable with conditions

[ash3]

I want to fill missing observation in status variable on 2 condition

1. if bucket =4 then status= "bad"

2. if previous bucket ="bad" and current bucket <4 then status = "recover"

so based on these two condition all missing obs should be "recover" but could not apply this logic on sas. Please help

id  bucket status

1    0   good

1    4    bad

1    0    ""

1    0   ""

1    1    ""

1    2   ""

1    3   ""

1    4    bad

[PeterClemmensen]

2 points:

1. Your desired result indicate that the logic should not be 'if previous bucket ..' . It should be 'if any of the previous bucket values within the same id group equals 4.
2. I take it that the logic should hold for different by-groups. 

Try the code below.

data have;
input id bucket;
datalines;
1 0 
1 4 
1 0 
1 0 
1 1 
1 2 
1 3 
1 4 
2 0 
2 4 
2 0 
2 0 
2 1 
2 2 
2 3 
2 4 
;

data want(drop = prev_4);
   set have;
   by id;

   if first.id then prev_4 = 0;
   if bucket = 4 then prev_4 = 1;

   length status $20;

   status = ifc(bucket = 4, 'bad', 'good');

   if prev_4 = 1 & bucket < 4 then status = 'recover';

   retain prev_4;
run;

Result:

id  bucket  status
1   0       good
1   4       bad
1   0       recover
1   0       recover
1   1       recover
1   2       recover
1   3       recover
1   4       bad
2   0       good
2   4       bad
2   0       recover
2   0       recover
2   1       recover
2   2       recover
2   3       recover
2   4       bad

[andreas_lds]

What should happen in this case?

id  bucket status
42    0   good
42    0   ?
42    0   ?
42    1   ?
42    2   ?
42    3   ?
42    4    bad

Or is such a case not possible?