计算1/1-1/2+1/3……+1/99-1/100

#define  _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>

int main()
{
    int i = 1;
    double sum = 0.0;
    int a = 1;
    for (i = 1; i <= 100; i++)
    {
        sum +=a* 1.0 / i;
        a = -a;
    }
    printf("%lf\n", sum);
    return 0;
}//计算1/1-1/2+1/3……+1/99-1/100