static void Main(string[] args)
{
DanhSachHinhHoc ds = new DanhSachHinhHoc();
ds.Nhap();
Console.WriteLine(ds);
Console.WriteLine(10);
Console.ReadKey();
}
public DanhSachHinhHoc TimDSHinhVuongMin()
{
DanhSachHinhHoc kq = new DanhSachHinhHoc();
float min = TimMinHinhVuong();
//foreach(var h in ds)
//{
// if(h is HinhVuong && h.TinhDT()==min)
// {
// kq.Them(h);
// }
//}
//return kq;
kq.ds.AddRange(ds.FindAll(x => x is HinhVuong && x.TinhDT() == min));
return(kq);
}