程序代码：

# include <stdio.h>

int main(void)
{
    float sigh, sum=1, term, i;

    for (i=2; i<=100; ++i)
    {
        term=(-1)*(1/i);
        sum=sum+term;
        ++i;
        sigh=1/i;
        sum=sum+sigh;
    }
    printf("%f\n", sum);

    return 0;
}