Original link: http://blog.csdn.net/wxq1987525/article/details/6619529
1. The subclass and parent class return value parameters are the same, the function name is the same, and the virtual keyword is the type of the object that determines which function is called.
2. Subclasses and parent classes as long as the function name is the same, without the virtual keyword, the object of the subclass has no way to call a function with the same name as the parent class, the parent class has a function with the same name hidden, or a function class::funtion_name with the same name can be forced to call the parent class.
3. The subclass and parent parameters are different, the function name is the same, there is the virtual keyword, there is no polymorphism, the object of the subclass has no way to call the parent class with the same name function, the parent class has the same name function is hidden, you can also force call the parent class with the same name function Class::funtion_name.
4. Subclass and Parent class return value is different, parameter is same, function name is same, there is virtual keyword, error C2555 compiler does not allow function name parameter same return value different function overload.
Names of C + + subclasses and parent class member functions