判断字符串问题

Question

字符串"sdfadsfasfsd"用什么函数判断有几个"a"

Answer 1

function StrSubCount(const Source,Sub:string):integer;
var Buf:string;
    Len,i:integer;
begin
   Result:=0;
   Buf:=Source;
   i:=Pos(Sub, Buf);
   Len:=Length(Sub);
  while i <> 0 do
    begin
    Inc(Result);
    Delete(Buf,1,i+Len-1);
    i:=Pos(Sub,Buf);
  end;
end;

Answer 2

另一简单方法:
procedure TForm1.Button1Click(Sender: TObject);
var
  t:tstringlist;
begin
   t:=tstringlist.Create;
   t.Delimiter:='a';
   t.DelimitedText:='sdfadsfasfsd';
   ShowMessage(inttostr(t.count-1));  // t.count-1就是a的个数
   t.free;
end;