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); }