Night Coding (Yahya suite)

Program suite;
Uses Wincrt;
Var
  f: Text;

Procedure creation (Var f:Text);
Begin
  Assign (f,'c:\bac\Suite.txt');
End;

function max (m:Integer): Integer;
Var
  i,n,x1,x2,e: Integer;
  echange: Boolean;
    ch:string;
    aux:char;
Begin
    str(m,ch);
    n := Length(ch);
  Repeat
    echange := False;
    For i:=1 To n-1 Do
      Begin
        Val (ch[i],x1,e);
        Val (ch[i+1],x2,e);
        If x1<x2 Then
          Begin
            aux := ch[i];
            ch[i] := ch[i+1];
            ch[i+1] := aux;
            echange := True;
          End;
      End;
    n := n-1;
  Until echange= False;
val (ch,x1,e);
max:=x1;

End;
function invers (n:integer):integer;
Var
ch,ch1:string;
e,i:integer;
Begin
str (n,ch);
ch1:='';
for i:=Length(ch) DownTo 1 Do
    ch1:=ch1+ch[i];
val (ch1,n,e);
invers:=n;
end;
Procedure traitement (Var f:Text);
Var
  u,i: Integer;
  t: Array [1..50] Of Integer;
Begin
  Rewrite (f);
  Writeln ('Saisir le premier terme U0');
  Readln (u);
  Writeln (f,u);
    t[1] := max(u)-invers(max(u));
  i := 1;
      Repeat
    i := i+1;
    t[i] := max(t[i-1])-invers(max(t[i-1]));
    Writeln (f,t[i]);
  Until max(t[i-1])-invers(max(t[i-1]))=max(t[i])-invers(max(t[i]));
    close (f);
End;
Begin
  creation (f);
  traitement (f);
End.