学习for while switch 循环生成的图

从书本《C#入门经典第五版》上记录下来的学习for  while switch 循环生成的图。

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            double realCoord, imagCoord;
            double realTemp, imagTemp, realTemp2, arg;
            int iterations;
            for (imagCoord = 1.2; imagCoord >= -1.2; imagCoord -= 0.05)
            {
                for (realCoord = -0.6; realCoord <= 1.77; realCoord += 0.03)
                {
                    iterations = 0;
                    realTemp = realCoord;
                    imagTemp = imagCoord;
                    arg = (realCoord * realCoord) + (imagCoord * imagCoord);
                    while ((arg < 4) && (iterations < 40))
                    {
                        realTemp2 = (realTemp * realTemp) - (imagTemp * imagTemp) - realCoord;
                        imagTemp = (2 * realTemp * imagTemp) - imagCoord;
                        realTemp = realTemp2;
                        arg = (realTemp * realTemp) + (imagTemp * imagTemp);
                        iterations += 1;
                    }
                    switch (iterations % 4)
                    {
                        case 0:
                            Console.Write(".");
                            break;
                        case 1:
                            Console.Write("o");
                            break;
                        case 2:
                            Console.Write("O");
                            break;
                        case 3:
                            Console.Write("@");
                            break;
                    }
                }
                Console.Write("\n");
            }

            Console.ReadKey();

        }

    }
}