近似计算
Time Limit:1000MS Memory Limit:65536K
Total Submit:198 Accepted:95
Description
计算pi/4=1-1/3+1/5-1/7+....+1/n,
Input
n
Output
根据该算式计算的pi的值(精确6位有效数字)
Sample Input
100
10000
1
Sample Output
3.121595
3.141393
4.000000
Source
lrj程序入门
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace AK1119 {
class Program {
static void Main(string[] args) {
string sb;
while ((sb = Console.ReadLine()) != null) {
int n = int.Parse(sb);
double sum = 0;
int sign = 1;
for (int i = 1; i <= n; i += 2) {
sum += 1.0 / i * sign;
sign *= -1;
}
sum *= 4.0;
Console.WriteLine(sum.ToString("0.000000"));
}
}
}
}