multiple-inheritance

问题 EDIT3: Please be sure to clearly understand what I am asking before answering (there are EDIT2 and lots of comments around). There are (or were) many answers which clearly show misunderstanding of the question (I know that's also my fault, sorry for that) Hi, I've looked over the questions on virtual inheritance ( class B: public virtual A {...} ) in C++, but did not find an answer to my question. I know that there are some issues with virtual inheritance, but what I'd like to know is in

问题 Is java.lang.Object superclass of all the custom class/objects inherited implicitly? I thought java didn't support multiple inheritance. The reason I ask is if I already inherit from another class in my custom class and again java is forcing implicit inheritance of java.lang.Object on top of it, is it not multiple inheritance? Also, is java.lang.class Class also the superclass for all custom classes/Objects? If not, how in java reflections we can get the type of class for any class passed or

问题 I know that having diamond inheritance is considered bad practice. However, I have 2 cases in which I feel that diamond inheritance could fit very nicely. I want to ask, would you recommend me to use diamond inheritance in these cases, or is there another design that could be better. Case 1: I want to create classes that represent different kinds of "Actions" in my system. The actions are classified by several parameters: The action can be "Read" or "Write". The action can be with delay or

问题 Suppose I have this variadic base class-template: template <typename ... Types> class Base { public: // The member foo() can only be called when its template // parameter is contained within the Types ... pack. template <typename T> typename std::enable_if<Contains<T, Types ...>::value>::type foo() { std::cout << "Base::foo()\n"; } }; The foo() member can only be called when its template-parameter matches at least one of the parameters of Base (the implementation of Contains is listed at the

问题 Considering my previous question, I try to implement what I need. The following is the content of a django app models.py. from neo4django.db import models from neo4django.auth.models import User as AuthUser class MyManager(models.manager.NodeModelManager): def filterLocation(self,**kwargs): qs = self.get_query_set() if 'dist' in kwargs: qs = qs.filter(_where_dist=kwargs['dist']) elif 'prov' in kwargs: qs = qs.filter(_where_prov=kwargs['prov']) elif 'reg' in kwargs: qs = qs.filter(_where_reg

问题 This question is for C++03, not C++11. I have a case where I am using CRTP with multiple inheritance, and I am curious to know if there is a way to remove the redundancy that is created when specifying the type of B below. #include "boost/typeof/typeof.hpp" #include "boost/units/detail/utility.hpp" #include <iostream> #include <string> struct One{}; struct Two{}; template<typename T> struct Type { static std::string name(void) { return boost::units::detail::demangle(typeid(T).name()); } };

问题 Let A, B, C, D be Moose classes. Let both B and C inherit from A. Let also D inherit from both B and C. What will happen with "duplicate" properties (properties from A present in both B and C)? 回答1: See Method Dispatch Order in Modern Perl : Method dispatch order (or method resolution order or MRO) is obvious for single-parent classes. Look in the object's class, then its parent, and so on until you find the method or run out of parents. Classes which inherit from multiple parents (multiple

问题 Suppose there is this interface: class A{ public: virtual foo()=0; }; And a class B which implements this interface: class B:public A{ public: virtual foo(){} //Foo implemented by B } Finally, a class C which has classes A and B as base classes: Class C : public A, public B { }; My question is, there is a way to tell the compiler that the implementation for foo is the one from class B without doing an explicit call to B::foo() ? 回答1: As @BenVoigt pointed out in the comments, the below answer

问题 I am building a scheduling platform with tasks for a current project Let's say there are some Global Constraints (money, people, etc.) for the project, and that each tasks also has individual Constraints. The big deal is that I have to match each Global Constraint to every Constraint of the tasks of a same project Now the real big deal, is that in addition to having a nature (financial -> Float, people -> Integer) the constraints can also have a type (ex : costs of wages, costs of raw

问题 I have two classes in Lua. One inherits another. test1 = {test1Data = 123, id= {0,3}} function test1:hello() print 'HELLO!' end function test1:new (inp) inp = inp or {} setmetatable(inp, self) self.__index = self return inp end test2 = {} function test2:bye () print ('BYE!', self.id) end function test2:new_inst_test (baseClass, inp) inp = inp or {} setmetatable(inp, self) self.__index = self if baseClass then setmetatable( inp, { __index = baseClass } ) end return inp end a = test1:new(