【C】#牛牛学数列3#
牛牛学数列3
https://www.nowcoder.com/practice/f65c726d081c4160a9356eabf0dc21d9
#include <stdio.h>
#include <math.h>
int main() {
int n;
float ret = 0.0, tmp = 0.0;
scanf("%d", &n);
for(int i = 1; i <= n; i++){
tmp += pow(-1, i - 1) * (2 * i - 1);
ret += 1.0 / tmp;
}
printf("%.3f", ret);
return 0;
}
