ISBN

IDENTIFICATION DIVISION.
PROGRAM-ID.         ISBN.

AUTHOR.             Linsley Meadows.

DATE-WRITTEN.       February 2019.

INSTALLATION.       On-line compiler.

SECURITY.           No specific security.

REMARKS.            ISBN -- International Standard Book Number.

*> The purpose of this program is to take a short (10 digit) ISBN and covert it 
*> to the long (13 digit) form, and vice versa. 
*>
*> In printed form ISBN components are separated by hyphens which are ignored 
*> in this implementation. 
*>
*> The format of an ISBN is MMM-L-NNNNNNNN-C
*> where MMM is 978 (or possibly 979) to identify it as a IBN 
*>         L is a language code (0 or 1 for English)
*>         NNNNNNNN is acombination of publisher / inprint and book number.
*>                   these 2 components are of variable length
*>         C is a check digit (0-9 in the long version, and 0-9,X n the short)

*> The shirt versuin excludes the MMM component. 

ENVIRONMENT DIVISION.
CONFIGURATION SECTION.
SOURCE-COMPUTER. ON-LINE.
OBJECT-COMPUTER. ON-LINE. 

DATA DIVISION.
WORKING-STORAGE SECTION.

*> INDICATORS, SUBSBRIPTS ETC.

77  CONVERSION-TYPE                             PIC A. 
    88  CONVERT-TO-13                                           VALUE "L", "l".
    88  CONVERT-TO-10                                           VALUE "S", "s".
    88  STOP-CONVERSIONS                                        VALUE "X", "x".
    88  VALID-CONVERSION-TYPE                                   VALUES "X","x","L","l","s","S".
    
77  S                                           PIC 99          USAGE COMP.

*> Definitions for the 2 forms of the ISBN 

01  ISBN-13                                     PIC X(13).

01  ISBN-13-COMPONENTS REDEFINES ISBN-13                        USAGE DISPLAY.
    05  ISBN-13-IDENT                           PIC 999.
        88 VALID-ISBN-13-IDENT                                  VALUES "978", "979".
    05  ISBN-13-LANGUAGE                        PIC 9. 
    05  ISBN-13-PUB-BOOK                        PIC 9(8).
    05  ISBN-13-CHECK-DIGIT                     PIC 9.
        88 VALID-ISBN-13-CHECK-DIGITS                           VALUES "1","2","3","4","5",
                                                                       "6","7","8","9","0".
                                                                       
01  ISBN-13-CHARACTERS REDEFINES ISBN-13.
    05  ISBN-13-CHAR                            PIC X           OCCURS 13 TIMES. 


01  ISBN-10                                     PIC X(10).

01  ISBN-10-COMPONENTS REDEFINES ISBN-10                         USAGE DISPLAY.
    05  ISBN-10-LANGUAGE                        PIC 9. 
    05  ISBN-10-PUB-BOOK                        PIC 9(8).
    05  ISBN-10-CHECK-DIGIT                     PIC X.
        88 VALID-ISBN-10-CHECK-DIGITS                           VALUES "1","2","3","4","5",
                                                                       "6","7","8","9","0",
                                                                       "X","x".
                                                                       
01  ISBN-13-CHARACTERS REDEFINES ISBN-10.
    05  ISBN-10-CHAR                            PIC X           OCCURS 10 TIMES.

PROCEDURE DIVISION.

*> Execute main loop until uuser indcates the end by entering the 
*> stop code of X or x.

PERFORM MAIN-LOOP UNTIL STOP-CONVERSIONS.

STOP RUN.

MAIN-LOOP.
*>>>>>>>>>

ACCEPT CONVERSION-TYPE.
DISPLAY CONVERSION-TYPE. *> NOT REQUIRED IN LIVE VESION

EVALUATE TRUE
      WHEN CONVERT-TO-13
         PERFORM GENERATE-ISBN-13;

      WHEN CONVERT-TO-10
         PERFORM GENERATE-ISBN-10;
         
      WHEN STOP-CONVERSIONS
         CONTINUE; *> Do nothing 

      WHEN OTHER
         DISPLAY "Invalid Conversion Type: " & CONVERSION-TYPE & " Valid values are: S, L OR X"; 
         
 END-EVALUATE.
    

GENERATE-ISBN-13.
*>>>>>>>>>>>>>>>>

DISPLAY "CONVERT TO 13".

*> Intialise the receiving 13 character area

MOVE 978 TO ISBN-13-IDENT. *> standard book identifier

MOVE ZERO TO    ISBN-13-LANGUAGE,       *> 0 or 1 for English
                ISBN-13-PUB-BOOK,       *> Publisher & unique Book   
                ISBN-13-CHECK-DIGIT.    *> 0-9 


GENERATE-ISBN-10. 
*>>>>>>>>>>>>>>>>

DISPLAY "CONVERT TO 10".

MOVE ZERO TO    ISBN-10-LANGUAGE,       *> 0 or 1 for English
                ISBN-10-PUB-BOOK.       *> Publisher & unique Book   
MOVE SPACE TO   ISBN-10-CHECK-DIGIT.    *> 0-9, X