程序退出时，向量 被销毁，您不需要确保它。您需要确保 _CrtDumpMemoryLeaks 在销毁后被调用，如果您不希望将分配的内存报告为leaked：

The vector is destroyed when the program exits, you don't need to ensure it. You do need to ensure that _CrtDumpMemoryLeaks is called after that destruction if you don't want it to report the allocated memory as "leaked":

int main()
{
    { Subject subject; }
    _CrtDumpMemoryLeaks();
    return 1;
}