C# Console Daire çizdirme

C# Console Daire çizdirme
 {
static void Main(string[] args)
{
  
  double radius;
  double thickness = 0.4;
  ConsoleColor BorderColor = ConsoleColor.Yellow;
  Console.ForegroundColor = BorderColor;
  char symbol = '*';
  do
  {
    Console.Write("Enter radius:::: ");
    if (!double.TryParse(Console.ReadLine(), out radius) || radius <= 0)
    {
      Console.WriteLine("radius have to be positive number");
    }
  }
  while (radius <= 0);
  Console.WriteLine();
  double rIn =radius- thickness, rOut = radius + thickness;
  for (double y = radius; y >= -radius; --y)
  {
    for (double x = -radius; x < rOut; x += 0.5)
    {
      double value = x * x + y * y;
      if (value >= rIn * rIn && value <= rOut * rOut)
      {
        Console.Write(symbol);
      }
      else
      {
        Console.Write(" ");
      }
    }
    Console.WriteLine();
  }
  Console.ReadKey();
}
 
}