convert pascal code to c ?

program shfrovalka;
uses crt;
  var text:string;
  m,k,c,men:integer;
procedure cez(var text:string; var k:integer);
  begin
  clrscr;
   writeln('vvedite isxodniy text ');
    write('$~/> ');
    read(text);
   write('vvedite klu4 shifrovani9 ');
    readln(k);
   for m:=1 to length(text) do
    begin
     c:=ord(text[m])+k;
     if c>256 then c:=c-256;
     text[m]:=chr(c);
    end;
end;
procedure desh (var text:string);
  begin
   writeln('vvedite kluch deshifrovki' );
   readln(k);
    for m:=1 to length(text) do
     begin
      c:=ord(text[m])-k;
       if c<256 then c:=c+256;
      text[m]:=chr(c);
     end;
  end;
begin
  repeat
    clrscr;
    writeln('1 - shifrovka ');
    writeln('2 - deshifrovka ');
    writeln('3 - sosto9nie texta ');
    readln(men);
     case men of
      1:cez(text,k);
      2:desh(text); U?
      3:begin
         writeln(text);
         readkey;
        end;
     end;
  until men = 0;
end.