prog2.cbl

identification division.
program-id. prog2.
environment division.
input-output section.
file-control.
select customer-file
     assign to "custfile"
     organization is line sequential
     file status is customer-status.

data division.
file section.
fd customer-file.
01 customer-record.
     05 customer-id                pic 9(3).
     05 customer-name              pic x(20).
     05 customer-age               pic xx.

working-storage section.
01  customer-status pic xx.
     88  eof-customer-file     value "10".

linkage section.
01  customer-info.
     05  requested-age.
        10  low-age              pic x(2).
        10  high-age             pic x(2).
     05  age-group-count           pic 9(3).

procedure division using customer-info.
main-logic.
     perform count-customers.
     goback.
count-customers.
     move zero to age-group-count.
     open input customer-file.
     perform until eof-customer-file
        read customer-file next record
        at end
           continue
        not at end
           if customer-age >= low-age and
              customer-age <= high-age
              add 1 to age-group-count
           end-if
        end-read
     end-perform.
     close customer-file.