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  1.     program main;
  2.   const n=65;
  3.   type A=array[0..n] of char;
  4.   const alpha:A=('А','Б','В','Г','Д','Е','Ё','Ж','З','И',
  5.                  'Й', 'К','Л','М','Н','О','П','Р','С','Т',
  6.                  'У','Ф','Х','Ц','Ч','Ш','Щ','Ъ','Ы','Ь',
  7.                  'Э','Ю','Я', 'а','б','в','г','д','е','ё',
  8.                  'ж','з','и','й','к','л','м','н','о','п',
  9.                  'р','с','т','у','ф','х','ц','ч','ш','щ',
  10.                  'ъ','ы', 'ь','э','ю','я');
  11.  
  12.   {Поиск индекса символа в алфавите}
  13.   function indexOf(c:char; arr:A):integer;
  14.   var i:integer;
  15.       index:integer;
  16.   begin
  17.     for i:=1 to n do
  18.       if (c=arr[i]) then 
  19.         index:=i;
  20.     indexOf:=index;
  21.   end;
  22.  
  23.   {Поиск наибольшего общего делителя}
  24.   function gcd(a,b:integer):integer;
  25.   begin
  26.     while(a>0) and (b>0) do
  27.       begin
  28.         if a>b then
  29.           a:=a mod b
  30.         else
  31.           b:=b mod a;
  32.       end;
  33.     gcd:=a+b;
  34.   end;
  35.   {Поиск обратного элемента в кольце по mod n}
  36.   function reversed(m:integer):integer;
  37.   var r:integer;
  38.       i:integer;
  39.   begin
  40.     m:=m mod n;
  41.     r:=-1;
  42.     for i:=1 to n do
  43.       if((i*m) mod n = 1) then
  44.         begin
  45.           r:=i;
  46.           break;
  47.         end;
  48.     reversed:=r;
  49.   end;
  50.  
  51.   {Шифрование и дешифрование применяет стандартные формулы
  52.    аффинного шифра}
  53.   function encrypt(txt:string; m,k:integer):string;
  54.   var i:integer;
  55.       c:char;
  56.       index:integer;
  57.   begin
  58.     m:=m mod n;
  59.     k:=k mod n;
  60.     if (gcd(m,n)<>1) then
  61.       begin
  62.         encrypt:='для однозначного шифрования m должен быть взаимно прост с n';
  63.         exit;
  64.       end;
  65.     for i:=1 to length(txt) do
  66.       begin
  67.         c:=txt[i];
  68.         index:=indexOf(c,alpha);
  69.         index:=(m*index+k) mod n;
  70.         txt[i]:=alpha[index];
  71.       end;
  72.     encrypt:=txt;
  73.   end;
  74.  
  75.   function decrypt(txt:string; m,k:integer):string;
  76.   var i:integer;
  77.       c:char;
  78.       index:integer;
  79.       reversed_m:integer;
  80.   begin
  81.     k:=k mod n;
  82.     reversed_m:=reversed(m);
  83.     for i:=1 to length(txt) do
  84.       begin
  85.         c:=txt[i];
  86.         index:=indexOf(c,alpha);
  87.         index:=(reversed_m*(index-k) mod n);
  88.         txt[i]:=alpha[index];
  89.       end;
  90.     decrypt:=txt;
  91.   end;
  92.   var m:integer;
  93.       k:integer;
  94.       txt:string;
  95.   begin
  96.     txt:='Шуршалка';
  97.     {Параметры ключа (m,k)}
  98.     m:=11;
  99.     k:=4;
  100.     writeln('Шифрование');
  101.     writeln('***>',encrypt(txt,m,k));
  102.     writeln('Дешифрование');
  103.     writeln('***>',decrypt(txt,m,k));
  104.   end.
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin
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Standard input is empty
compilation info 
Free Pascal Compiler version 2.2.0 [2009/11/16] for i386
Copyright (c) 1993-2007 by Florian Klaempfl
Target OS: Linux for i386
Compiling prog.pas
prog.pas(4,22) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,27) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,32) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,37) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,42) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,47) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,52) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,57) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,62) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(4,67) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,22) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,28) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,33) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,38) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,43) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,48) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,53) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,58) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,63) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(5,68) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,22) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,27) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,32) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,37) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,42) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,47) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,52) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,57) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,62) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(6,67) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,22) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,27) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,32) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,38) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,43) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,48) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,53) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,58) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,63) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(7,68) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,22) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,27) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,32) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,37) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,42) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,47) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,52) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,57) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,62) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,67) Error: Incompatible types: got "Constant String" expected "Char"
prog.pas(8,67) Fatal: There were 50 errors compiling module, stopping
Fatal: Compilation aborted
Error: /usr/bin/ppc386 returned an error exitcode (normal if you did not specify a source file to be compiled)
stdout
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Standard output is empty
https://ideone.com/gWyQ4t
language:
Pascal (fpc 3.0.4)
created:
11 years ago
visibility:
public

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