using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace 练习5._6
{
class Program
{
static void Main(string[] args)
{
//Console.WriteLine("请输入梯形的长");
//string str = Console.ReadLine();
//double num1 =Convert.ToDouble(str ) ;
//Console.WriteLine("请输入梯形的宽");
//string str1 = Console.ReadLine();
//double num2 = Convert.ToInt32(str1);
//Console.WriteLine("请输入梯形的高");
//string str3 = Console.ReadLine();
//double num3 = Convert.ToDouble(str3);
//Console.WriteLine("请算出梯形的面积");
//double res = (num1 + num2) * num3 / 2;
//Console.WriteLine(res);
Console.WriteLine("请输入圆的半径");
string str = Console.ReadLine();
double n = Convert.ToDouble(str);
//Console.WriteLine("请输入圆的周长");
Console.WriteLine("圆的周长:"+(2*n*3.14));
Console.WriteLine("圆的面积:"+(n*n*3.14));
Console.ReadKey();
