using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    // an abstract class with (undefined) methods
    abstract class Shape {
	abstract public double Area ();
    }

  // the Suqare class derives from shape, but overrides Area
  class Square : Shape
  {
      public static int no = 0;
      public static double area = 0.0;
      public double Width { get ; set ;  }
      public override double Area() { return this.Width * this.Width;  }
      public Square(double x) { this.Width = x ; Square.no++; Square.area += this.Area(); }
  }

  // the Circle class derives from shape, but overrides Area
  // Hint:  use Math.PI
    class Circle : Shape
  {
      public static int no = 0;
      public static double area = 0.0;
      public double Radius { get ; set ;  }
      public override  double Area() { return Math.PI * this.Radius * this.Radius;    }
      public Circle(double r) { this.Radius = r ; Circle.no++; Circle.area += this.Area(); }
  }


  // the Rectangle class derives from shape, but overrides Area
  class Rectangle : Shape
  {
      public static int no = 0;
      public static double area = 0.0;
      public double Width { get ; set ; }
      public double Height { get ; set ;  }
      public override double Area() { return  this.Width * this.Height ;   }
      public Rectangle(double w, double h) { this.Width = w ; this.Height = h ;  Rectangle.no++; Rectangle.area += this.Area(); }
  }
  // the main class
  class Program
  {
        private static double TotalArea(Shape[] arr, int n) { 
	  double res = 0.0;
	  for (int i = 0; i < n; i++) {
            Console.WriteLine("Current element: " + arr[i].ToString());
	    res += arr[i].Area();
	  }
	  return res;
	}
        
        static void Main(string[] args)
        {
	    // Just one object is used like this (doesn't need overloading):
	    Circle c = new Circle(3);
	    Console.Write("This is a cricle of radius {0} covering an area of {1}", c.Radius, c.Area());

	    // this will NOT work: you can't instantiate an abstract class
	    // Shape q = new Shape();

	    // this container can be used with different geometric objects
            Shape[] all = new Shape[80];
            int i = 0;
	    all[i++] = c;
            Console.Write("Enter shape (c for circle, s for square, r for rectangle, q to quit):");
            string str = Console.ReadLine();
            while (str.CompareTo("q") != 0)
            {
                switch (str)
                {
                    case "c":
                        {
                            Console.Write("Enter radius of circle: ");
                            string str1 = Console.ReadLine();
                            int x = Convert.ToInt32(str1);
                            all[i++] = new Circle(x);
                            break;
                        }
                    case "s":
                        {
                            Console.Write("Enter width of square: ");
                            string str1 = Console.ReadLine();
                            int x = Convert.ToInt32(str1);
                            all[i++] = new Square(x);
                            break;
                        }

                    case "r":
                        {
                            Console.Write("Enter width of rectangle: ");
                            string str1 = Console.ReadLine();
                            int w = Convert.ToInt32(str1);
                            Console.Write("Enter height of rectangle: ");
                            str1 = Console.ReadLine();
                            int h = Convert.ToInt32(str1);
                            all[i++] = new Rectangle(w, h);
                            break;
                        }
                    default: Console.WriteLine("Unknown input {0}", str); break;
                }
                Console.Write("Enter shape (c for circle, s for square, r for rectangle, q to quit):");
                str = Console.ReadLine();

            }
            Console.WriteLine("Created {0} circles, {1} squares and {2} rectangles", Circle.no, Square.no, Rectangle.no);
            Console.WriteLine("Area of all circles: {0}; area of all squares: {1}; area of all rectangles {2}", Circle.area, Square.area, Rectangle.area);
            double total = Circle.area + Square.area + Rectangle.area;
            Console.WriteLine("Total area is {0}", total);
            Console.WriteLine("Total area computed by TotalArea method is {0}", TotalArea(all,i));


        }
  }
  class ProgramFixed
  {
        static void MainFixed(string[] args)
        {
            Square sq1 = new Square(5);
            Square sq2 = new Square(2);
            Rectangle rec1 = new Rectangle(4, 5);
            Console.WriteLine("Created {0} squares and {1} rectangles", Square.no, Rectangle.no);
            Console.WriteLine("Area of all squares: {0}; area of all rectangles {1}", Square.area, Rectangle.area);
            double w = sq1.Area() + sq2.Area() + rec1.Area();
            double w0 = Square.area + Rectangle.area;
            if (w == w0)
            {
                Console.WriteLine("Total area is {0}", w);
            }
            else
            {
                Console.WriteLine("Something went wrong computing the total area");
            }

        }
  }
}