calculator2.cob

       PROCEDURE DIVISION.
       CALCULATOR-ROUTINE.
           DISPLAY "COBOL CALCULATOR" LINE 4 POSITION 10 ERASE SCREEN.
           PERFORM ACCEPT-NUM1.
           PERFORM ACCEPT-OPERATOR THRU ACCEPT-OPERATOR-EXIT.
           PERFORM ACCEPT-NUM2.
           IF OPERATOR = "+"
              ADD NUM1, NUM2 GIVING RESULT.
           IF OPERATOR = "-"
              SUBTRACT NUM2 FROM NUM1 GIVING RESULT.
           IF OPERATOR = "*"
              MULTIPLY NUM1 BY NUM2 GIVING RESULT.
           IF OPERATOR = "/"
              DIVIDE NUM1 BY NUM2 GIVING RESULT.
           MOVE RESULT TO RESULT-EDIT.
           DISPLAY NUM1-TXT LINE 12 POSITION 10.
           DISPLAY OPERATOR LINE 12 POSITION 14.
           DISPLAY NUM2-TXT LINE 12 POSITION 16.
           DISPLAY "=" LINE 12 POSITION 20.
           DISPLAY RESULT-EDIT LINE 12 POSITION 22.
           STOP RUN.
       ACCEPT-NUM1.
           DISPLAY "Enter First Number : " LINE 6 POSITION 10.
           ACCEPT NUM1-TXT LINE 6 POSITION 31 PROMPT ECHO.
           IF NUM1-TXT (1:1) NUMERIC OR
              NUM1-TXT (2:1) NUMERIC OR
              NUM1-TXT (3:1) NUMERIC
              MOVE NUM1-TXT TO NUM1 WITH CONVERSION
              DISPLAY NUM1-TXT LINE 6 POSITION 31
           ELSE
              GO TO ACCEPT-NUM1.
       ACCEPT-OPERATOR.
           DISPLAY "Enter Operator (+,-,*,/): " LINE 8 POSITION 10.
           ACCEPT OPERATOR LINE 8 POSITION 36 PROMPT ECHO.
           IF OPERATOR NOT EQUAL "+" AND
              OPERATOR NOT EQUAL "-" AND
              OPERATOR NOT EQUAL "*" AND
              OPERATOR NOT EQUAL "/"
              GO TO ACCEPT-OPERATOR.
       ACCEPT-OPERATOR-EXIT.
           EXIT.
       ACCEPT-NUM2.
           DISPLAY "Enter Second Number: " LINE 10 POSITION 10.
           ACCEPT NUM2-TXT LINE 10 POSITION 31 PROMPT ECHO.
           IF NUM1-TXT (1:1) NUMERIC OR
              NUM2-TXT (2:1) NUMERIC OR
              NUM2-TXT (3:1) NUMERIC
              MOVE NUM2-TXT TO NUM2 WITH CONVERSION
              DISPLAY NUM2-TXT LINE 10 POSITION 31
           ELSE
              GO TO ACCEPT-NUM2.