static void Main(string[] args)
{
Rectangle r = new Rectangle(2, 4);
Console.WriteLine("a=" + r.Side1 + " b=" + r.Side2);
r.AreaCalculation(r.Side1, r.Side2);
Console.Write("Area rectangle: " + r.Area);
r.PerimetrCalculation(r.Side1, r.Side2);
Console.WriteLine();
Console.Write("Perimetr rectangle: " + r.Perimetr);
Console.WriteLine();
Console.WriteLine("------------------------------------------------");
Console.Write("Enter a=");
r.Side1 = double.Parse(Console.ReadLine());
Console.Write("Enter b=");
r.Side2 = double.Parse(Console.ReadLine());
r.AreaCalculation(r.Side1, r.Side2);
Console.Write("Area rectangle: " + r.Area);
r.PerimetrCalculation(r.Side1, r.Side2);
Console.WriteLine();
Console.Write("Perimetr rectangle: " + r.Perimetr);
}