C ++/Java knowledge

[C ++ medium]
 

 
The three keywords public, private, and protected are the access mode qualifiers used to access class members and inherit the base class. In the member access mode, public indicates that the data members and functions of the class can be accessed by the class objects and derived classes. Private; your class can be accessed, but the derived class cannot. Protected protection type; its class and derived class can access its own private-type members. The difference between it and private is that it treats the derived class differently.
 

 
[In java]
 

Public visible all protected subclass visible default package visible private this class visible
 

Java static methods can be called without instantiating objects
 

 
The main function must use the static method.