Application 2 (Les Algorithmes Recurrents)

Program app2;
Uses Wincrt;
Var
  a: Char;
  n,i: Integer;
  ch: String;
Function Thue_Morse (ch:String): String;
Var
  x: String;
  i: Integer;
Begin
  x := '';
  For i:=1 To Length (ch) Do
    Begin
      If ch[i]='0' Then
        x := x+'01';
      If ch[i]='1' Then
        x := x+'10';
    End;
  Thue_Morse := x;
End;
Begin
  Repeat
    Write ('Saisir A: ');
    Readln (a);
  Until a In ['0','1'];
  Repeat
    Write ('Saisir N: ');
    Readln (n);
  Until (0<n) And (n<30);
  ch := a;
  Clrscr;
  Writeln ('U0->',ch);
  For i:=1 To n Do
    Begin
      ch := Thue_Morse(ch);
      Writeln ('U',i,'->',ch);
    End;
End.