Bac 2020 (Rework)

Program bac2020;
Uses Wincrt;
Var
  f1,f13,f7: Text;
Procedure remplir (Var f1:Text);
Var
  nb,i: Integer;
    n:string;
Begin
  Repeat
    Writeln ('Saisir NB: ');
    Readln (nb);
  Until (nb>=1);
  Rewrite (f1);
  For i:=1 To nb Do
    Begin
      Readln (n);
      Writeln (f1,n);
    End;
  Close (f1);
End;
Function divis13 (n:String): Boolean;
Var
  sg,s,e,v: Integer;
Begin
  s := 0;
  sg := -1;
  While Length(n)>=3 Do
    Begin
      Val (Copy(n,Length(n)-2,3),v,e);
      s := s+v*sg;
      sg := -sg;
      Delete (n,Length(n)-2,3);
    End;
  Val (n,v,e);
  s := s+v*sg;
  divis13 := Abs(s) Mod 13=0;
End;
Function divis7 (n:String): Boolean;
Var
sg,p,e,s,x,i:integer;
ch:string;
Begin
  ch := '132';
  sg := 1;
  While Length(n)>=2 Do
    Begin
      i := 0;
            s := 0;
      Repeat
        i := i+1;
        Val (n[Length(n)],x,e);
        Val (ch[i],p,e);
        s := s+x*p*sg;
        Delete (n,Length(n),1);
        If (i=3) Then
          Begin
            i := 0;
            sg := -sg;
          End;
      Until (n='');
      Str (abs(s),n);
    End;
    divis7:=(n='7') or (n='0');
End;
Procedure traitement (Var f1,f13,f7:Text);
Var
  n: string;
Begin
  Reset (f1);
  Rewrite (f7);
  Rewrite (f13);
  While Not (Eof(f1)) Do
    Begin
      Readln (f1,n);
      If divis7 (n) Then
                Writeln (f7,n);
      If divis13 (n) Then
        Writeln (f13,n);
    End;
  Close (f1);
  Close (f7);
  Close (f13);
End;
Begin
    Assign (f1,'c:\bac\Nombres.txt');
  Assign (f13,'c:\bac\divis13.txt');
  Assign (f7,'c:\bac\divis7.txt');
    remplir (f1);
    traitement (f1,f13,f7);
End.