c--------------------------------------------------------------------------
c  Reading one s-file at a time in a loop and extract SPEC and AMPG and 
c  AMSG for each station.
c
c  Some parameters are then modified and the modified event is written
c  to the output file.
c--------------------------------------------------------------------------c
c
c  For detail on parameters and variables names, see rea.inc
c
c  To compile this program, use command make sample_read_write_s on sun
c  and nmake sample_read_write_s on pc
c
c
      implicit none                       ! force delcaration of all variables
      include 'seidim.inc'                ! dimensions for rea block
      include 'seisan.inc'                ! dimensions for rea block
      include 'rea.inc'                   ! parameter common bliock

      character*80 data(5000)             ! s-file with data in text array
      character*80 err_text               ! error text
      character*80 infile                 ! input file

      logical all                         ! true: read all data, false: headers
      integer code                        ! error return code
      integer nevent                      ! number of events in file
      integer i, j                        ! counter
      real  :: ampS(100)                  ! amplitude of S-wave 
      real  :: ampP(100)                  ! amplitude of P-wave
      character*5 cur_sta

c
c   open output file

      open(2,file='spec_amp.out',status='unknown')
    
c
c   get input file name, check if exist
c

 9    continue
      write(6,*) 'Give input file'
      read(5,'(a)') infile
      open(1,file=infile,status='old',err=10)
      goto 11
 10    continue
      write(6,*)' No such input file'
      goto 9
 11   continue
c
      all=.true.                  ! read all parameters
      nevent=0                    ! initialize counter

c
c-----------------------------------------------------------------
c  Loop to read events start here
c-----------------------------------------------------------------
c

  50  continue
c
c   read all parameters for one event form file unit 1
c
      call rea_event_in(1,all,data,code)
c
c   check if end of file (code=1), if so jump out of loop
c
      if(code.eq.1) goto 1000
c
      nevent=nevent+1               ! count events
c     
c   write on screen a bit info on event, number of headers and
c   total number of records
c
      write(6,*)' Number of headers and number of records',
     *rea_nhead,rea_nrecord

      write(*,*) ' nhead, nspec ',rea_nhead,rea_nspec

c
c   write the whole first header line
c
      write(6,'(a)') data(1)(1:79)
c
c   some example of modifying event
c

c---------------------------------------------------------
c   select all traces with s-wave spectral values, print
c   on screen station, time and log moment
c----------------------------------------------------------
c
      do i=1,rea_nphase
       if(rea_phase(i)(1:5).eq.'SPECS') then
        cur_sta = rea_stat(i) 
       do j=1, rea_nphase
        if (rea_stat(j)(1:5).eq.cur_sta .and. 
     +rea_phase(j)(1:4).eq.'AMPG') then
          ampP = rea_amp(j)
        else if (rea_stat(j).eq.cur_sta .and. 
     +rea_phase(j)(1:4).eq.'AMSG') then
          ampS = rea_amp(j)
        end if
       end do
       print *, rea_stat(i),' ',rea_comp(i),' ',ampP,' ', ampS 	
c              write(6,'(1x,a4,1x,a5,2i2,f6.1,f6.2)')
c     *        rea_stat(i), rea_comp(i), rea_hour(i),
c     *        rea_min(i),rea_sec(i),rea_moment(i)
       end if
      end do
c
c------------------------------------------------
c   write out all magnitudes form all hypocneters
c------------------------------------------------
c
      write(6,'(1x,6(f4.1,a1,a4,1x))') (hyp_mag_all(i),
     *hyp_mag_type_all(i),hyp_mag_agency_all(i),i=1,rea_nmag)
c
c   write out modified event, the array data has also been modified
c
       call rea_event_out(2,all,data,code)
c
c   get next event
c
      goto 50
c
c     end of file
c
 1000 continue
c
      write(6,*)            ! blank line
      close(2)              ! close output file
      write(6,*) 'Number of events in input file', nevent
      write(6,*) 'Output file name is sample_read_write_s.out'

      stop
      end