constructor for NotificationCenter must explicitly initialize the member receiverModel which does not have a default constructor应该怎么解决

这个错误提示是因为在创建NotificationCenter类的对象时，receiverModel成员变量没有默认构造函数，需要显式地进行初始化。解决方法如下：

1.在NotificationCenter类的构造函数中初始化receiverModel对象。

例如：

class NotificationCenter {
public:
    NotificationCenter() : receiverModel(ReceiverModel()) {}
private:
    ReceiverModel receiverModel;
};

2.给receiverModel添加默认构造函数。

例如：

class ReceiverModel {
public:
    ReceiverModel() {}
};

以上两种方法都可以解决这个错误提示。