用循环语句来写，刚学C语言

Question

根据用户输入的正整数n，求1-1/2+1/3-1/4+一直加到+(-1)^（n+1）/n的值

Answer 1

#include<stdio.h>
int main()
{
    int n,i = 0;
    double sum = 0;
    int flag = 1;
    printf("请输入n的值:\n");\
    scanf("%d",&n);
    for (i = 1; i <= n; i++)
    {
        sum = sum + flag * (1.0 / i);
        flag = -flag;
    }
    printf("结果为：%lf ", sum);
    return 0;
}