题解 | #牛牛学数列3#
牛牛学数列3
https://www.nowcoder.com/practice/f65c726d081c4160a9356eabf0dc21d9
#include <stdio.h>
float qudao(int num)//取倒数
{
return 1.000000/num;
}
int fenmu(int n)//求分母
{
if(n%2==0)
return -n;
else
return n;
}
int main()
{
int num;
int j;
scanf("%d",&num);
int Fenmu;
float result=0;
for(j = 1;j<=num;j++)//实现累加求和
{
Fenmu = fenmu(j);
result += qudao(Fenmu);
}
printf("%.3f",result);
return 0;
}
