实验2-2 C#通过公式计算π的值以及任意半径圆面积

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace pi
{
class Program
{
static void Main(string[] args)
{
double sum = 0.5, t, t1, t2, t3, p = 0.5 * 0.5;
int odd = 1, even = 2;
t = t1 = t2 = 1.0;
t3 = 0.5;
while (t > 1e-10)
{
t1 = t1 * odd / even;
odd += 2;
even += 2;
t2 = 1.0 / odd;
t3 = t3 * p;
t = t1 * t2 * t3;
sum += t;
}
Console.WriteLine("请输入一个圆的半径");
string s = Console.ReadLine();
double nnnn = Convert.ToInt32(s);
double bbb;
bbb = nnnn * nnnn * sum * 6;
Console.WriteLine("{0}", bbb);
Console.WriteLine("\nPI={0,10:f8}", sum * 6);
Console.Read();
}
}
}