I have some time working with Qt and I have always used private slots. I have never thought too much about it.

Qt Private Slot

槽的存取权限决定了谁能够与其相关联。同普通的 C 成员函数一样，槽函数也分为三种类型，即 public slots、private slots 和 protected slots。 public slots：在这个区内声明的槽意味着任何对象都可将信号与之相连接。.

Currently, I have an application with several dialog boxes, which in turn have a number of widgets. The functionalities that must be executed when the user interacts with such widgets
are implemented as slots. Example: Clicking on a particular button zooms in on an image that is displayed.

C++ Private Slots

Now I ask myself:

Public Slots

Is it correct that such slots are private?
Would it be of any use to make such public slots?
What is expected (standard) in these cases?