求1/1-1/2+1/3-1/4+....+1/99-1/100

#include "stdio.h"
void main()
{
	int i = 0;
	double sum=0.0;
	int flag = 1;
	 for (i=1;i<=100;i++)
	 {
		 sum+=flag*(1.0 / i);
		 flag = -flag;
	 }
	 printf("1/1-1/2+1/3...+1/99-1/100=%lf",sum);
}