static void Main(string[] args)
{
DIEM a = new DIEM(); a.nhap(); a.hien();
DIEM b = new DIEM(); b.nhap(); b.hien();
Console.WriteLine("khoang cach la" + a.khoangcach(b));
Console.ReadKey();
}
public double khoangcach(DIEM b)
{
return(Math.Sqrt(Math.Pow(b.x - this.x, 2) + Math.Pow(b.y - this.y, 2)));
}