Question : problem of do while loop iin foxpro

I have a table named "output", like below:

type            sales            Trank
small            100.00           0
small              55.5             0
small              213.10         0
large              76.12           0
large              12.00           0
medium           2133.1        0
medium             66.88        0
medium            424.11       0

while the result should be add the rank to the different types like:
type            sales            Trank
small            100.00           2
small              55.5             3
small              213.10         1
large              76.12           1
large              12.00           2
medium           2133.1        1
medium             66.88        3
medium            424.11       2

my program code:

SELECT 1
USE output
INDEX ON type TO key
SET INDEX TO key
GO top
rankno = 0
DO WHILE !EOF()
SEEK "SMALL"
        IF FOUND()
              REPLACE Trank WITH rankno
        ENDIF
            rankno = rankno + 1
IF !FOUND()
        WAIT WINDOW "NO RECORD"
        LOOP
ENDIF
        SKIP      
ENDDO
CLOSE ALL

but it prompted me with "no record..."

and I tried another code:
SELECT 1
USE output
SCAN
  rankno = 1
  FOR lnI = 1 TO FCOUNT()  
    IF ALLTRIM(EVALUATE(FIELD('type')))='SMALL' then
    replace Trank WITH rankno
    endif
  rankno = rankno + 1
  NEXT
ENDSCAN

but I got ALL fields under column "type" filled with 8.....
pls kindly help...

Answer : problem of do while loop iin foxpro

USE output
INDEX ON type+str(sales)  tag typesales descending
do while not eof()
     lcType=type
     lnRank=0
     SCAN WHILE lcType=type
          lnRank=lnRank+1
          REPLACE TRANK WITH lnRank
     ENDSCAN
ENDDO