procedure TForm1.newClick(Sender: TObject);
var
f:textfile;
filename:string;
begin
filename:='a.txt';
if not fileexists(filename) then
begin
assignfile(f,filename);
rewrite(f);
closefile(f);
e.Text:='ok';
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
var
f:textfile;
filename:string;
begin
filename:='a.txt';
assignfile(f,filename);
rewrite(f);
writeln(f,'aa');
closefile(f);
end;
procedure TForm1.Button1Click(Sender: TObject);
var
f:textfile;
filename:string;
str:string;
begin
filename:='a.txt';
assignfile(f,filename);
reset(f);
readln(f,str);
closefile(f);
e.Text:=str;
end;