*之前的预期构造函数，析构函数或类型转换（第45行）

Question

第45行的主题

//Server.h
class Server : public QTcpServer
{
Q_OBJECT
    public:
        typedef QHash<int, Student*> Students;
         ...
        Students* getStudents      () const;
         ...
    private:
        Students _students;
};

//Server.cpp
void Server::setPort( quint16 port )
{
    _port = port;
}

quint16 Server::getPort() const
{
    return _port;
}
Students* Server::getStudents() const // line 45
{
    return _students;
}

Answer 1

Students实际上是一个“嵌套类型”，编译器无法弄清楚它所引用的内容，因为它还没有看到Server::上下文。你需要：

Server::Students* Server::getStudents() const