inheritance

问题 This "Code A" is the code of my base class and i am extending this class to another class "Code B". The problem is when i run my app my application has stopped. Is there any problem with my Base class or i not call them properly? Activity is registered in manifest file. Code A public class PrepaidBase extends Activity { PrepaidBase pb = new PrepaidBase(); private String number = ""; public void alertDialogShow(Context context, String title, String message, String _number) { this.number =

问题 Let's say I have some base abstract class and three different classes that derive and implement its methods. Is there is a 'Type' object like as in C#? Or in other words, how do I get instances of all these classes? #ModuleBase.cpp class ModuleBase { }; #Module1.cpp class Module1 : public virtual ModuleBase { }; #Module2.cpp class Module2 : public virtual ModuleBase { }; #Module3.cpp class Module3 : public virtual ModuleBase { }; 回答1: You can create instanceof like methods that can detect the

问题 Let's say I have some base abstract class and three different classes that derive and implement its methods. Is there is a 'Type' object like as in C#? Or in other words, how do I get instances of all these classes? #ModuleBase.cpp class ModuleBase { }; #Module1.cpp class Module1 : public virtual ModuleBase { }; #Module2.cpp class Module2 : public virtual ModuleBase { }; #Module3.cpp class Module3 : public virtual ModuleBase { }; 回答1: You can create instanceof like methods that can detect the

问题 The problem is quite simple. If a class B inherit a class A and wants to override a ´classmethod´ that is used as a constructor (I guess you call that a "factory method"). The problem is that B.classmethod will want to reuse A.classmethod , but then it will have to create an instance of the class A, while it subclasses the class A - since, as a classmethod, it has no self. And then, it doesn't seem the right way to design that. I did the example trivial, I do more complicate stuff by reading

问题 I wanted the class C inherits from class A its virtual functions, and class D(nested class in class C) inherits from class B(nested class in class A) its data fields, here is what I have. file1.h class A{ public: virtual void foo()=0; class B{ public: int data; }; }; file2.h class C : public A{ public: class D : public A::B{ }; }; file2.cpp void C::foo(){//code} C::D::D():data(0){//Bad initialization list, error being data is not a member of C::D even it should inherits from its base class

问题 A bit of a feasibility question for you regarding Maven. Particular, on whether we can define properties in an aggregating pom and then inject them into the referenced modules, thus allowing that module to locally overwrite the default properties defined in the inheritance hierarchy. If you're interested in specifics I'll describe my setup. Before I do though, let me just say that we have discussed our project structure as a team extensively and it fits our needs very well. We are not looking

问题 A bit of a feasibility question for you regarding Maven. Particular, on whether we can define properties in an aggregating pom and then inject them into the referenced modules, thus allowing that module to locally overwrite the default properties defined in the inheritance hierarchy. If you're interested in specifics I'll describe my setup. Before I do though, let me just say that we have discussed our project structure as a team extensively and it fits our needs very well. We are not looking

问题 I am new to Stack Overflow and am teaching myself C++, but am still quite a beginner. After completing a nice chunk of the book I am using (which may be considered out dated and/or not a great book) I decided to re-enforce some concepts by trying them on my own, referencing the book only if needed, but I appear to be stuck. The concepts I am trying to tackle are inheritance, polymorphism, abstract data types (ADT), and separating the code for my classes into header files (.h) and C++ file (

问题 I am new to Stack Overflow and am teaching myself C++, but am still quite a beginner. After completing a nice chunk of the book I am using (which may be considered out dated and/or not a great book) I decided to re-enforce some concepts by trying them on my own, referencing the book only if needed, but I appear to be stuck. The concepts I am trying to tackle are inheritance, polymorphism, abstract data types (ADT), and separating the code for my classes into header files (.h) and C++ file (

问题 I have some classes that inherit from each other. All classes contain the same method (let us call it mymethod ), whereby the children overwrite the base class method. I want to generate a documentation for mymethod in all classes using sphinx. Suppose mymethod takes an argument myargument . This argument has the same type and meaning for both the base method as well as the inherited method. To minimize redundancies, I would like to write the documentation for myargument only for the base