program-id. Program1 as "CPBOL_MASTERFILES.Program1".

       environment division.
       input-output section.
           file-control.   select inin assign to "C:\Users\1630955\Desktop\SHITS\First.txt" organization is line sequential.
                           select outout assign to "C:\Users\1630955\Desktop\SHITS\COBOL_TRANS.txt"
                           organization is indexed record key is custNO.
       data division.
       fd inin.
       01 inf.
           05 custNOI pic x(5).
           05 custNAI pic x(20).
           05 DOPI pic 9(8).
           05 AOPI pic 9(9).

       fd outout.
       01 outf.
           05 custNO pic x(5).
           05 custNA pic x(20).
           05 DOP pic 9(8).
           05 AOP pic 9(9).

       working-storage section.

       01 loopf pic x value 'y'.
       01 selection pic 9.

       01 custNumber pic 9(5).
       01 custName pic x(20).
       01 custDOP pic 9(8).
       01 custAOP pic 9(5).

       procedure division.
       open input inin
       open output outout

       perform until loopf = "n"
       read inin
           at end
           move "n" to loopf

           not at end
           write outf
               invalid key
                   display custNO"  Already exist"
               not invalid key
                  move space to outf
           move custNOI to custNO
           move custNAI to custNA
           move DOPI to DOP
           move AOPI to AOP
           end-write



       end-read
       end-perform
       close inin
       close outout
           stop run.

         end program Program1.