function TForm1.HAn: String;
Const
yy = 1000;
Var
a : Array [0..25] Of Char;
Temp : Char;
i, FromSit, ToSit : Integer;
begin
Randomize;
For i := 0 To 25 Do
a[i] := Chr(i+65);
//随机交换关联序号
For i := 1 To yy Do
Begin
//生成随机数
FromSit := Random(26);
ToSit := Random(26);
//交换序号
Temp := a[FromSit];
a[FromSit] := a[ToSit];
a[ToSit] := Temp;
End;
Result := a;
end;