#include <stdio.h>
int main()
{
	int sign=1;
	double deno=2.0,sum=1.0,term;   //定义双精度类型的变量 
	while (deno<=100)
	{
		sign=-sign;
		term=sign/deno;
		sum=sum+term;
		deno=deno+1;
	}
	printf("%f\n",sum);
	return 0;
}