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 a = 0;
scanf("%d",&a);
double num = 0;
for (int i =1 ; i<= a;i++)
{
num += 1.0 / (i % 2 == 0? -i : i);
}
printf("%.3lf", num);
return 0;
}
