OJ2011.txt

//2011
/*
int m,n;//m个测试例子，每个n都要求前n项和
double sum;
while(scanf("%d",&m)!=EOF){
    for (int k = 0; k < m ; ++k) {//执行m次测试
        while(scanf("%d",&n)!=EOF){//每次输入n
            if(n<0||n>=1000)
                break;
            for (int i = 1; i <=n ; ++i){
                (i%2==0)?sum-=(double)1/i:sum+=(double)1/i;
            }
            printf("%.2f\n",sum);
            sum=0;
        }
    }
}*/