PROGRAM SUM
C*This program will read in data from two or more data files
C*and output the sum of the columns from each file.
C
C*J.E. Penner-Hahn  6/11/89
C
	LOGICAL*1 FILE_IN(60),FILE_OUT(60),TEMP_FILE(60)
	LOGICAL*1 STRING(123)
	REAL DATA(1000,12),DATA_TEMP(1000,12)
	INTEGER N_SC_COPY(16),N_SC_AVG(16),N_TEMP(16)
	DATA MAXCHN,N_POINT_MAX,LUNTTO,LUNTTI/0,0,5,6/
C-------------------------------------
C*Get file names and open files
C
1	WRITE (LUNTTO,800)
800	FORMAT (//'$Enter name of the first file to sum: ')
	READ (LUNTTI,801) FILE_IN
801	FORMAT (60A1)
	IF (FILE_IN(1).EQ.' ') CALL EXIT
12	CONTINUE
	N_LST_CHAR=0
	DO 10 I=60,1,-1
	IF (FILE_IN(I).NE.' '.AND.N_LST_CHAR.EQ.0) N_LST_CHAR=I
	IF (FILE_IN(I).EQ.' ') FILE_IN(I)=0
10	CONTINUE
	OPEN (UNIT=1,NAME=FILE_IN,ERR=15,STATUS='OLD',
     1	FORM='FORMATTED')
	GO TO 19
15	WRITE (LUNTTO,890) FILE_IN
890	FORMAT (' ***** Unable to open ',60A1)
	GO TO 1
19	CONTINUE
	DO 20 I=1,60
	FILE_OUT(I)=FILE_IN(I)
	IF (I.GT.N_LST_CHAR) FILE_OUT(I)=0
20	CONTINUE
	FILE_OUT(N_LST_CHAR+1)='S'
32	WRITE (LUNTTO,802) FILE_OUT
802	FORMAT (' Enter output filename ['60A1']'/'$ :')
	READ (LUNTTI,801) TEMP_FILE
	IF (TEMP_FILE(1).NE.' ') THEN
	  DO 30 I=60,1,-1
	  IF (TEMP_FILE(I).EQ.' ') TEMP_FILE(I)=0
	  FILE_OUT(I)=TEMP_FILE(I)
30	  CONTINUE
	ENDIF
	OPEN (UNIT=2,NAME=FILE_OUT,STATUS='NEW',ERR=35,
     1	FORM='FORMATTED',RECL=123)
	GO TO 400
35	WRITE (LUNTTO,890) FILE_OUT
	GO TO 32
C------------------------------
C*Get rid of header.  Penultimate header line has # as 2nd character.
400	READ (1,840,END=900) STRING
840	FORMAT (123A1)
C-N_MAX_POINT is zero for the first file processed.
	IF (N_POINT_MAX.EQ.0) WRITE (2,840) STRING
	IF (STRING(2).EQ.'#') THEN
	  READ (1,840) STRING
	  IF (N_POINT_MAX.EQ.0) WRITE (2,840) STRING
	  GO TO 500
	ELSE
	  GO TO 400
	ENDIF
C----------------------------
C*Begin processing file
500	CONTINUE
	N_POINT=1
505	READ (1,850,END=600) (DATA_TEMP(N_POINT,J),J=1,12)
850	FORMAT (F11.1,F12.0,10F10.0)
	N_POINT=N_POINT+1
	IF (N_POINT.GT.1000) THEN
	  WRITE (LUNTTO,851)
851	  FORMAT (///' Processing truncated at 1000 points///')
	ENDIF
C-If we haven't yet determined the number of channels used, do so.
C-For this purpose, any "channel" whose value is 0.0 for point 1 is
C-considered to be unused.
	IF (MAXCHN.EQ.0) THEN
	  DO 510 J=12,3,-1
	    IF (DATA_TEMP(1,J).NE.0.) MAXCHN=J
	    IF (DATA_TEMP(1,J).NE.0.) GO TO 515
510	  CONTINUE
C-All data in line one is zero
	  WRITE (LUNTTO,9003) FILE_IN
9003	  FORMAT (1X,60A1,' does not appear to be a data file')
	  GO TO 1
	ENDIF
515	CONTINUE
	GO TO 505
C-Add these data to the DATA matrix
600	CONTINUE
	IF (N_POINT_MAX.EQ.0) THEN
C-If this is the first file . . .
	  N_POINT_MAX=N_POINT-1
	ELSE
C-If this is not the first file, confirm that all points are there
	  IF (N_POINT-1.LT.N_POINT_MAX) THEN
	    WRITE (LUNTTO,860) FILE_IN,N_POINT-1,N_POINT_MAX
860	    FORMAT (1X,60A1,' contains ',I4,' data point.'/
     1	    ' Previous file(s) had ',I4,'.  Should file be included'
     2	    ' in average'/'$anyway? ')
	    READ (LUNTTI,840) STRING
	    IF (STRING(1).EQ.'Y'.OR.STRING(1).EQ.'y') THEN
	      GO TO 610
	    ELSE
	      GO TO 700
	    ENDIF
	  ENDIF
	ENDIF
C-Add data to sum
610	CONTINUE
	DO 630 I=1,N_POINT_MAX
	  DO 620 J=3,MAXCHN
	  DATA(I,J)=DATA_TEMP(I,J)+DATA(I,J)
620	  CONTINUE
630	CONTINUE
C-Get a new file to average (if appropriate)
700	CONTINUE
	WRITE (LUNTTO,870)
870	FORMAT ('$Enter name of the next file to be averaged: ')
	READ (LUNTTI,801) FILE_IN
	IF (FILE_IN(1).EQ.' ') GO TO 750
	CLOSE (UNIT=1)
	DO 710 I=60,1,-1
	IF (FILE_IN(I).EQ.' ') FILE_IN(I)=0
710	CONTINUE
	OPEN (UNIT=1,NAME=FILE_IN,ERR=715,STATUS='OLD',
     1	FORM='FORMATTED')
	GO TO 400
715	WRITE (LUNTTO,890) FILE_IN
	GO TO 700
C-Finished reading files - output data, close unit 2, and
C-re-initialize variables for a new sum.
750	CONTINUE
	WRITE (LUNTTO,852) N_POINT_MAX,MAXCHN
852	FORMAT (//' Writing output file.  ',I4,' data points,'
     1	I3,' channels.')
	DO 765 I=1,N_POINT_MAX
	WRITE (2,850) (DATA_TEMP(I,J),J=1,2),
     1	(DATA(I,K),K=3,MAXCHN)
765	CONTINUE
	CLOSE (UNIT=2)
	MAXCHN=0
	N_POINT_MAX=0
	GO TO 1
C----------------------
C*Program exits
C*Unexpected end during header
900	WRITE (LUNTTO,9000)
9000	FORMAT (//'****Unexpected end of file during header'///)
	IF (N_POINT_MAX.EQ.0) GO TO 1
	IF (N_POINT_MAX.GT.0) GO TO 700
	END