下面C++代码用于记录多个输入数中的最大数和最小数（输入 -999 则输入结束），相关说法错误的是（ ）。

cin >> now_num;
min_num = max_num = now_num;
while (now_num != -999)
{
    if (max_num < now_num)
        max_num = now_num;
    if (min_num > now_num)
        min_num = now_num;
    cin >> now_num;
}
cout << min_num << ' ' << max_num;