[PAS] Any to any number system

program project1;

uses
    crt, DOS;

const Digits: String='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';

function AnyToDec(inputString: String; numberSystem: Integer): Int64;
var
   X, i: Integer;
begin
     Result := 0;

     for i := 1 to Length(inputString) do
     begin
          X := Pos(inputString[i], Digits) - 1;
          Result := Result*numberSystem + X;
     end;
end;

function DecToAny(input: Int64; numberSystem: Integer): String;
var
   X: Integer;
begin
     Result := '';

     repeat
           X := input mod numberSystem;
           input := input div numberSystem;
           Result := Digits[X + 1] + Result;
     until (input = 0) ;
end;

var
   inputSystem, outputSystem: Int64;
   inputValue: String;

begin
     write('system z ktorego bedziesz konwertowal: ');
     readLn(inputSystem);
     write('system do ktorego bedziesz konwertowal: ');
     readLn(outputSystem);

     write('Wprowadz liczbe do konwersji w systemie z ktorego chcesz konwertowac: ');
     readLn(inputValue);

     writeln( DecToAny( AnyToDec( inputValue, inputSystem ), outputSystem ) );


     ReadKey;

end.