static void Main(string[] args)
{
Point n = new Point(2, 4);
Circle m = new Circle(5, 2, 4);
m.Show();
}
static void Main(string[] args)
{
Console.Write("请输入长方形的长：");
double length = double.Parse(Console.ReadLine());
Square square = new Square(length);
square.Show(square.Area());
Console.Write("请输入圆的半径：");
double radius = double.Parse(Console.ReadLine());
Circle circle = new Circle(radius);
circle.Show(circle.Area());
}
