Computer Science 101

with:  Erik Oosterwal

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Selected Range Copy


This routine will parse an input string for a set of numbers in the form of any number followed by more numbers separated by commas or pairs of numbers separated by dashes.

Back in 1988 I was working on a contract programming project that was supposed to interface a PC with a Chessell model 4001 Data recorder for doing a specific type of test at a local corporation.  In those days, Windows hadn't been invented yet and if you wanted to have on screen editing capability you had to program all the keyboard input and screen output stuff yourself.  One of the requests for this particular project was the ability to copy setup configuration data from one channel to some number of other channels.  For instance, if you had set up channel 3 to accept voltage input from between 0 and 150 V and you wanted to use the same configuration on channels 5, 6, 9, 10, 11, 12, 24, 25, 26, and 30, you could do it manually, which took time and was difficult due to the weird pressure sensitive push buttons on the front of the Chessell data recorders, or you could use this routine from the PC to do the same thing in about 5 seconds.

Using the scenario from the previous paragraph, you could copy channel 3 configuration to channels 5, 6, 9, 10, 11, 12, 24, 25, 26, and 30 by entering in each of those channel numbers separated by commas, or you could group adjacent channel numbers with a dash in between them like this:  5, 6, 9-12, 24-26, 30.  This seemed much more intuitive and saved a number of keystrokes.

The original code appears below:



C     *    FIND NUMBER OF SUBSTRINGS WITHIN THE STRING
   65 SUBLEN=0
C
      STRING(LEN+1)='.'
      DO 20 I = 1,LEN
           IF(STRING(I).EQ.' ')THEN
                DO 10 J = I,LEN-1
                     STRING(J)=STRING(J+1)
   10                CONTINUE
                STRING(LEN)='.'
                SUBLEN=SUBLEN+1
                ENDIF
   20      CONTINUE
C
      LEN=LEN-SUBLEN
      SUBLEN=0
C
      DO 40 I = 1,LEN-1
           IF((STRING(I).EQ.',').AND.(STRING(I+1).EQ.','))THEN
                DO 30 J = I,LEN-1
                     STRING(J)=STRING(J+1)
   30                CONTINUE
                STRING(LEN)='.'
                SUBLEN=SUBLEN+1
                ENDIF
   40      CONTINUE
C
      LEN=LEN-SUBLEN
      SUBLEN=0
C
      COMMA=1
      DO 50 I = 1,LEN
           IF(STRING(I).EQ.',')COMMA=COMMA+1
   50      CONTINUE
      STRING(LEN+1)=','
C
C     COPY THE VALUE TO THE SPECIFIED CHANNELS
      COUNTER=0
      DO 90 I = 1,COMMA
           START=0
           STOP=0
   60      COUNTER=COUNTER+1
           IF((STRING(COUNTER).GE.'0').AND.
     *          (STRING(COUNTER).LE.'9'))THEN
                STOP=STOP*10+ICHAR(STRING(COUNTER))-48
                IF(STOP.GT.30)STOP=30
                GOTO 60
                ENDIF
           IF(STRING(COUNTER).EQ.'-')THEN
                START=STOP
                STOP=0
                GOTO 60
                ENDIF
           IF(STRING(COUNTER).EQ.',')THEN
                IF(START.EQ.0)START=STOP
                DO 80 J = START,STOP
                     DO 70 K = BEGIN,END
                          DATAVAR(CHESNUM,(J-1)*43+K)=
     *                         DATAVAR(CHESNUM,(CHAN-1)*43+K)
   70                     CONTINUE
   80                CONTINUE
                ENDIF
   90      CONTINUE
C
   95 CALL XYPOSN(22,3)
      WRITE(6,110)
C
      CALL COLOR(44,37,1,0,0)
C
      DO 96 I = 1,30
           STRING(I) = ' '
           DATAVAR(CHESNUM,(I-1)*43+1) = CHAR(INT(I/10)+48)
   96      DATAVAR(CHESNUM,(I-1)*43+2) = CHAR(MOD(I,10)+48)
C

As time permits, I'll translate the code to be more easily read and describe the function of each portion.  In the mean time, if you have a need to write a routine that copies or moves data from one location to some set of other locations and you want to keep the input short and sweet, feel free to parse through the routine your self.




Discuss computer algorithms and other computer science topics at the Computer Algorithms blog page.

All code and original algorithms are © Erik Oosterwal - 1987-2008
Computer Science 101

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