Copyright © 2004
by Polaris Computing.
All rights reserved.
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Pascal Code for ISBN
Conversion
The following program converts a 10-character
ISBN to a 13-digit
ISBN with the "978" prefix, and vise versa. The
function ISBN1013 can be used to convert your currently existing ISBN's into
the new format.
You can use Borland Delphi to compile
the following code into a console application. Minor modifications might be needed if you use other compilers. The main
program simply passes an argument to one of the conversion functions,
ISBN1310 and ISBN1013, and conversions are all done by these functions.
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Language |
Pascal |
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Compiler |
Borland Delphi |
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Disclaimer: All sample
code contained herein is provide to you "AS IS." ALL IMPLIED
WARRANTIES, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF THE
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE EXPRESSLY
DISCLAIMED. |
(*
This program gets an argument from the command line.
If the argument is a 10-character SIBN, the program will
print the corresponding 13-gigit ISBN. If the argument
is a 13-digit ISBN, the program will print the
corresponding 10-character ISBN.
The main program only provides a way of testing . All the
conversion is done by the two functions: ISBN1310
and ISBN1013.
*)
program isbnconv;
{$APPTYPE CONSOLE}
uses
SysUtils;
var
ISBN: string;
(********************* Convert ISBN-13 to ISBN-10
**********************)
function ISBN1310(ISBN: string): string;
var
s9: string[9];
s10: string[10];
i, n: integer;
ErrorOccurred: boolean;
begin
ErrorOccurred := FALSE;
s9 := Copy(ISBN, 4, 9);
n := 0;
for i:=1 to 9 do begin
if NOT ErrorOccurred then begin
if s9[i] IN ['0'..'9'] then n := n +
(11-i)*(Ord(s9[i])-Ord('0'))
else ErrorOccurred := TRUE;
end;
end;
if ErrorOccurred then s10 := 'ERROR'
else begin
n := 11 - n mod 11;
if n=11 then s10 := s9 + '0'
else if n=10 then s10 := s9 + 'X'
else s10 := s9 + Char(Ord('0') + n);
end;
ISBN1310 := s10;
end;
(********************* Convert ISBN-10 to ISBN-13
**********************)
function ISBN1013(ISBN: string): string;
var
s12: string[12];
s13: string[13];
i, n: integer;
ErrorOccurred: boolean;
begin
ErrorOccurred := FALSE;
s12 := '978' + Copy(ISBN, 1, 9);
n := 0;
for i:=1 to 12 do begin
if NOT ErrorOccurred then begin
if s12[i] IN ['0'..'9'] then begin
if i mod 2 = 0 then n := n +
3*(Ord(s12[i]) - Ord('0'))
else n := n + Ord(s12[i]) - Ord('0');
end
else ErrorOccurred := TRUE;
end;
end;
If ErrorOccurred then s13 := 'ERROR'
else begin
n := n mod 10;
if n<>0 then n := 10 - n;
s13 := s12 + Char(Ord('0') + n);
end;
ISBN1013 := s13;
end;
(**************************** Main Program
*****************************)
begin
if ParamCount=1 then begin
ISBN := ParamStr(1);
if Length(ISBN)=10 then WriteLn(ISBN1013(ISBN))
else if Length(ISBN)=13 then WriteLn(ISBN1310(ISBN))
else WriteLn('Invalid ISBN.');
end
else WriteLn('USAGE: isbnconv ISBN');
end.
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