2020-07-04

//求圆周长和面积 /* using System;

namespace _5 { class Program { static void Main(string[] args) { Console.WriteLine(""); double r = double.Parse(System.Console.ReadLine()); const double pi = 3.14159; Console.WriteLine("{0}", 2 * pi * r); Console.WriteLine("{0}", pi * r * r); Console.ReadKey(); } } }