正负号变换

#define _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>

#include<math.h>

int main()

{

double mu = 0;

double sum = 0;

int flag = 1;

for (mu = 1; mu <= 100; mu++)

{

 sum +=flag* 1/mu;//+=求总和符号

 flag = -flag;

}

printf("%lf ", sum);