static void Main(string[] args)
{
Console.WriteLine("Nhap vao chieu dai:");
cd = int.Parse(Console.ReadLine());
Console.WriteLine("Nhap vao chieu rong:");
cr = int.Parse(Console.ReadLine());
HCN hcn1 = new HCN();
hcn1.SetHCN(cd, cr);
Console.WriteLine("Chu vi hcn la:{0}", hcn1.chuvi());
Console.WriteLine("Dien tich hcn la:{0}", hcn1.dientich());
Console.ReadLine();
}
