dimension iter(3000)
      character map*4,thismap*4,nextmap*4,infile*65,outfile*65
      character*8 sta,nextsta,s(3000),ans*1
      logical exists
      data n,line/2*0/
      print 100
  100 format (' Plouff, 11-94, PREPHTC.  Interactively  prepares a',
     1 ' file of station names',/,'  and associated hand TC''s for ',
     2 'input into program ADDTC, which updates plouff',/,'  file.  ',
     3 'The input into this program is the (sorted) output from pro',
     4 'gram ',/,'  MAPINDEX.  You could either type TC''s directly ',
     5 'from a map or refer to a',/,'  list, for example, superim',
     6 'posed on output from program MAPSTAS.')
      inquire (file='PREPHTC.PNT',exist=exists)
      if (exists) then
        print 101
  101   format (' You already have file PREPHTC.PNT that records ',
     1   'this program.',/,' DO YOU WANT TO STOP TO SAVE THE FILE?')
        read 501, ans
  501   format (a1)
        if (ans .eq. 'y' .or. ans .eq. 'Y' .or. ans .eq. ' ') stop
      end if
      print 102
  102 format (' TYPE the name of the output file from MAPINDEX:')
      read 565, infile
  565 format (a65)
      inquire (file=infile,exist=exists)
      if (.not. exists) then
        print 103
  103   format (' That file was not found.  Try once more.')
        print 102
        read 565, infile
        inquire (file=infile,exist=exists)
        if (.not. exists) then
          print 104
  104     format (' **STOP.  Input file again was not found.')
          stop
        end if
      end if
      print 105
  105 format (' TYPE a name for an output file of TC''s to be sub',
     1 'mitted to the ADDTC program:')
      read 565, outfile
      inquire (file=outfile,exist=exists)
      if (exists) then
        print 106
  106   format (' That output file already exists.  Do you want to ',
     1   'STOP to save it?')
        read 501, ans
        if (ans .eq. 'y' .or. ans .eq. 'Y' .or. ans .eq. ' ') stop
      end if
      open (15,file=infile,form='formatted',status='old')
      open (16,file='PREPHTC.PNT',form='formatted',status='unknown')
      write (16,100)
      open (7,file=outfile,form='formatted',status='unknown')
      write (16,201) infile,outfile
  201 format (' Your MAPINDEX file for input is:',/,3x,a65,/,
     1 ' Your output file of estimated TC''s is:',/,3x,a65)
      print 107
  107 format (' Type TC''s in response to a prompt of a ',
     1 'map name followed by station name.',/,' Typing a zero means',
     2 ' to skip that station.  Typing a negative number means',/,
     3 '  to select following options to stop or to skip ahead:',/,
     4 '  1--Skip to a station name to be typed',/,'  2--',
     5 'Skip to next map after this one',/,'  3--Skip to next map ',
     6 'name to be typed',/,'  4--Stop process (can append ',
     7 'later)',/,' Type hand TC''s in units of 0.01 mGal without ',
     8 'a decimal point.')
   50 read (15,150,end=9) map,sta
  150 format (2x,a4,1x,a8)
      line=line+1
c Skip " MAP" header at beginning or end of file or original filename.
      if (map .eq. ' MAP' .or. map .eq. 'Inpu') go to 50
   51 print 108, sta,map
  108 format (1x,a8,' (',a4,'):')
      read (5,*,err=8) itc
      if (itc) 52,50,53
c Negative number for TC; await further instruction.
   52 print 109
  109 format (' TYPE 1 (next sta #), 2 (go to next map), 3 (skip to ',
     1 'later map), or 4 (stop):')
      read (5,*,err=88) itype
      if (itype .lt. 1 .or. itype .gt. 4) go to 88
      go to (1,2,3,4), itype
    1 print 110
  110 format (' TYPE next 8-digit station name you want to skip to:')
      read 508, nextsta
  508 format (a8)
   11 read (15,150,end=19) map,sta
      line=line+1
      if (sta .eq. nextsta) go to 51
      go to 11
   19 print 619, sta
      write (16,619) sta
  619 format (' ***Premature stop.  Station ',a8,' was not found.')
      go to 9
    2 thismap=map
   21 read (15,150,end=29) map,sta
      line=line+1
      if (map .ne. thismap) go to 51
      go to 21
   29 print 629, map
      write (16,629) map
  629 format (' ***Premature stop.  No more maps were after ',a4)
      go to 9
    3 print 111
  111 format (' TYPE next 4-digit map name you want to skip to:')
      read 504, nextmap
  504 format (a4)
   31 read (15,150,end=39) map,sta
      line=line+1
      if (map .eq. nextmap) go to 51
      go to 31
   39 print 639, nextmap,map
      write (16,639) nextmap,map
  639 format (' ***Premature stop.  Requested map ',a4,' was not in ',
     1 'the file after map ',a4)
      go to 9
    4 write (16,649) map,sta
  649 format (' ***You stopped input after map ',a4,', station ',a8)
      go to 9
c Positive acceptable number for TC
   53 write (7,700) sta,itc
  700 format (a8,i4)
      n=n+1
      s(n)=sta
      iter(n)=itc
      if (n .eq. 3000) then
        print 160, sta
        write (16,160) sta
  160   format (' Wow!  You hit the limit of 3000 TC''s with station ',
     1    a8,/,' Take a break and start over where you must stop now.')
        go to 9
      end if
      go to 50
    8 print 800
  800 format (' You typed something that was not an integer number.  ',
     1 'Try again.')
      go to 51
   88 print 801
  801 format (' You typed an unacceptable response.  Try again.')
      go to 52
    9 print 609,     n,outfile
      write (16,609) n,outfile
  609 format (' A total of',i4,' stations were provided TC''s in ',
     1 'file:',/,3x,a65)
      print 902
  902 format (' Print file PREPHTC.PNT to see a record of the ',
     1 'updated stations.',/,' To optimize merging with ',
     2 'plouff file, sort PREPHTC output files.')
      if (n .eq. 0) then
        print 699
        write (16,699)
  699   format (' ***NO stations were updated')
        go to 99
      end if
      write (16,900)
  900 format (6('  STATION HTC'))
      write (16,901) (s(i),iter(i),i=1,n)
  901 format (6(1x,a8,i4))
   99 close (16)
      close (15)
      close (7)
      stop
      end