Initial data commit

Task/Parsing-RPN-calculator-algorithm/COBOL/parsing-rpn-calculator-algorithm.cobol

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+       IDENTIFICATION DIVISION.
+       PROGRAM-ID. RPN.
+       AUTHOR.  Bill Gunshannon.
+       INSTALLATION.
+       DATE-WRITTEN.  9 Feb 2020.
+      ************************************************************
+      ** Program Abstract:
+      **   Create a stack-based evaluator for an expression in
+      **   reverse Polish notation (RPN)   that also shows the
+      **   changes in the stack as each individual token is
+      **   processed as a table.
+      ************************************************************
+
+       DATA DIVISION.
+
+
+       WORKING-STORAGE SECTION.
+
+       01  LineIn               PIC X(25).
+       01  IP                   PIC 99
+                  VALUE 1.
+       01  CInNum               PIC XXXX.
+
+       01  Stack                PIC S999999V9999999
+               OCCURS  50 times.
+       01  SP                   PIC 99
+                  VALUE 1.
+       01  Operator             PIC X.
+       01  Value1               PIC S999999V9999999.
+       01  Value2               PIC S999999V9999999.
+       01  Result               PIC S999999V9999999.
+       01  Idx                  PIC 99.
+       01  FormatNum            PIC ZZZZZZ9.9999999.
+       01  Zip                  PIC X.
+
+       PROCEDURE DIVISION.
+
+       Main-Program.
+            DISPLAY "Enter the RPN Equation: "
+                     WITH NO ADVANCING.
+            ACCEPT LineIn.
+
+            PERFORM UNTIL IP GREATER THAN
+                          FUNCTION STORED-CHAR-LENGTH(LineIn)
+
+
+            UNSTRING LineIn DELIMITED BY SPACE INTO CInNum
+                    WITH POINTER IP
+
+            MOVE CInNum TO Operator
+
+            PERFORM Do-Operation
+
+            PERFORM Show-Stack
+
+            END-PERFORM.
+
+            DISPLAY "End Result: " FormatNum
+
+           STOP RUN.
+
+       Do-Operation.
+
+          EVALUATE Operator
+          WHEN "+"
+                        PERFORM Pop
+                        Compute Result = Value2 + Value1
+                        PERFORM Push
+
+          WHEN "-"
+                        PERFORM Pop
+                        Compute Result = Value2 - Value1
+                        PERFORM Push
+
+          WHEN "*"
+                        PERFORM Pop
+                        Compute Result = Value2 * Value1
+                        PERFORM Push
+
+          WHEN "/"
+                        PERFORM Pop
+                        Compute Result = Value2 / Value1
+                        PERFORM Push
+
+          WHEN "^"
+                        PERFORM Pop
+                        Compute Result = Value2 ** Value1
+                        PERFORM Push
+
+          WHEN NUMERIC
+                       MOVE Operator TO Result
+                       PERFORM Push
+          END-EVALUATE.
+
+
+       Show-Stack.
+
+              DISPLAY "STACK: " WITH NO ADVANCING.
+              MOVE 1 TO Idx.
+              PERFORM UNTIL (Idx = SP)
+                      MOVE Stack(Idx) TO FormatNum
+                      IF Stack(Idx) IS NEGATIVE
+                         THEN
+                              DISPLAY "    -" FUNCTION TRIM(FormatNum)
+                                             WITH NO ADVANCING
+                         ELSE
+                              DISPLAY FormatNum WITH NO ADVANCING
+                     END-IF
+                      ADD 1 to Idx
+              END-PERFORM.
+                      DISPLAY " ".
+
+       Push.
+
+             MOVE Result TO Stack(SP)
+             ADD 1 TO SP.
+
+       Pop.
+
+            SUBTRACT 1 FROM SP
+            MOVE Stack(SP) TO Value1
+            SUBTRACT 1 FROM SP
+            MOVE Stack(SP) TO Value2.
+
+
+       END-PROGRAM.