C + + abstract base class

The following statements about abstract classes and pure virtual functions are wrong
a) classes that have pure virtual functions are abstract classes and cannot be used to define objects
B) If a derived class of an abstract class does not implement a pure virtual function, it is also an abstract class
C) Declaration of pure virtual function ends with "= 0;"
D) Pure virtual function can not have function body

D Pure virtual function can define the function body, but the class is still an abstract class after the definition, if the subclass does not require calls, then the subclass function does not inherit the parent class pure virtual function implementation, and only inherit the interface, the function body is meaningless

This article from "not fat not skinny not ugly not handsome" blog, please be sure to keep this source http://jdmylove.blog.51cto.com/9688344/1594060

C + + abstract base class