C  shellitst.for or .f77  for comparison with shellitst.c and shellitst.ada
C  SHELLITST.FOR
C
      SUBROUTINE SHELLI(SIZE,ARR1,ARR2)
      IMPLICIT INTEGER (A-Z)
      CHARACTER*3  ARR1(*),TEMP1
      REAL         ARR2(*),TEMP2
      M=SIZE
20    M=M/2
      IF(M.LE.0) GO TO 120
      DO 100 J=1,SIZE-M
        I=J
60      CONTINUE
        IF(ARR1(I).GT.ARR1(I+M)) THEN
          TEMP1=ARR1(I)
          ARR1(I)=ARR1(I+M)
          ARR1(I+M)=TEMP1
          TEMP2=ARR2(I)
          ARR2(I)=ARR2(I+M)
          ARR2(I+M)=TEMP2
          I=I-M
          IF(I.GT.0) GO TO 60
        ENDIF
100   CONTINUE
      GO TO 20
120   RETURN
      END


      PROGRAM SHELLITST
      CHARACTER*3  ARR1(20)
      REAL         ARR2(20)
      DATA ARR1/'MMM','NNN','AAA','CCC','BBB','ZZZ','XXX',
     1          'PPP','QQQ','DDD','EEE','FFF','GGG','HHH',
     2          'III','JJJ','KKK','LLL','OOO','RRR'/
      DATA ARR2/1.,2.,3.,4.,5.,6.,7.,8.,9.,10.,11.,12.,13.,14.,
     1          15.,16.,17.,18.,19.,20./
      DO 10 I=1,20
        PRINT *,ARR1(I),' ',ARR2(I)
10    CONTINUE
      CALL SHELLI(20,ARR1,ARR2)
      PRINT *, 'Sorted by name'
      DO 20 I=1,20
        PRINT *,ARR1(I),' ',ARR2(I)
20    CONTINUE
      END