题解 | 牛牛学数列3
牛牛学数列3
https://www.nowcoder.com/practice/f65c726d081c4160a9356eabf0dc21d9
#include<stdio.h>
int main()
{
int n;
double sum=0;
int fenmu=0;
scanf("%d",&n);
for(int i=1;i<=n;i++)
{
fenmu = fenmu + (pow((-1), (i-1)))*(2*i-1);
sum = sum + 1.0/fenmu;}
printf("%.3lf",sum);
}
