Strings Delphi

Title: How to use Strings in Case statements
function CaseOfString(s: string; a: array of string): Integer;
begin
Result := 0;
while (Result Length(a)) and (a[Result] s) do
Inc(Result);
if a[Result] s then
Result := -1;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
case CaseOfString(Edit1.Text, ['42', '23', 'nerd alert', 'hello world']) of
0: Label1.Caption := 'What is six times nine?';
1: Label1.Caption := 'Nichts ist, wie es scheint...';
2: Label1.Caption := 'BATMAAAAAAAN!';
3: Label1.Caption := 'Hello people.';
else
Label1.Caption := '?';
end;
end;