C#动态求圆的面积
//Console.WriteLine("请输入半径:");
//double num3 = Convert.ToDouble(Console.ReadLine());
//Console.WriteLine("圆的面积为:" + (3.14 * num3 * num3));
//Console.ReadKey();
//double num3 = Convert.ToDouble(Console.ReadLine());
//Console.WriteLine("圆的面积为:" + (3.14 * num3 * num3));
//Console.ReadKey();