public class Program
{
private static void Main(string[] args)
{
try
{
Console.Write("请输入半径: ");
int r = Convert.ToInt32(Console.ReadLine());
double s = Math.PI*(Math.Pow(r, 2));
Console.WriteLine("半径为{0}圆的面积为{1}", r, s.ToString("F"));
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
}