multiple-inheritance

问题 I have a class: class Base; Also I have an interface class Interface; Next i'm creating a class class Derived : public Base, public Interface; If I have Base *object = new Derived; How can i cast object to Interface ? (of course if i know than object is actually a derived class) EDIT: I've tried dynamic_cast and static_cast (not compiled). So let me explain the problem a bit more: I have: class Object {...} class ITouchResponder { public: virtual bool onTouchBegan(XTouch *touch) = 0; virtual

问题 I have struggled with this design problem for some time. I will do my best to explain what I am trying to do and the various approached that I have seen, what I am trying and why. I work in a scientific computing environment where I deal with the same kinds of objects repeatedly. Imagine a galaxy which contains solar systems, each solar system contains planetary systems and each planetary system contains moons. To this end I think of the situation as a “has a” situation, and thus I have used

问题 We can achieve the same functionality as interfaces by using abstract classes, So why java doesn't allow the following code? abstract class Animals { public abstract void run(); } abstract class Animals1 { public abstract void run1(); } class Dog extends Animals,Animals1 { public void run() {System.out.println("Run method");} public void run1() {System.out.println("Run1 method");} } I know that multiple inheritance can be achieved by using only interfaces but the above code does the same

问题 According to the docs, super(cls, obj) returns a proxy object that delegates method calls to a parent or sibling class of type cls I understand why super() offers this functionality, but I need something slightly different: I need to create a proxy object that delegates methods calls (and attribute lookups) to class cls itself; and as in super , if cls doesn't implement the method/attribute, my proxy should continue looking in the MRO order (of the new not the original class). Is there any

问题 The scenario generating this is quite complex so I'll strip out a few pieces and give an accurate representation of the classes involved. /* This is inherited using SI by many classes, as normal */ class IBase { virtual string toString()=0; }; /* Base2 can't inherit IBase due to other methods on IBase which aren't appropriate */ class Base2 { string toString() { ... } }; /* a special class, is this valid? */ class Class1 : public IBase, public Base2 { }; So, is this valid? Will there be

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 6 years ago . I'm a Java programmer, learning to program in Go. So far I really like the language. A LOT more than Java. But there's one thing I'm a bit confused about. Java has interfaces because classes can inherit only from one class. Since Go allows multiple inheritance, what's the

问题 I am using Rails 3.2.2 with mongoid 2.4.6. In order to keep my collections small I am storing child objects to a base class in sepparate collections using the "store_in" statement. My code looks like this: class BaseClass include Mongoid::Document end class ChildClass1 < BaseClass store_in :child_1 end class ChildClass2 < BaseClass store_in :child_2 end It appears that the objects get randomly stored in or or the other child collection. An object of type Child1 sometimes gets stored in

问题 As I am working as a C# developer, I know that we can implement multiple inheritance by use of Interface . Can anybody please provide me link OR code for how to achieve multiple inheritance with C# . I want code for how to achieve multiple inheritance in C# with the use of Interface . Thanks in advance. 回答1: Here is a good example. http://blog.vuscode.com/malovicn/archive/2006/10/20/How-to-do-multiple-inheritance-in-C_2300_-2D00-Implementation-over-delegation-_2800_IOD_2900_.aspx A quick code

问题 This seems like a reasonable (and maybe simple?) scenario, but how would you do the following: Lets say I have 2 interfaces: Interface ISimpleInterface string ErrorMsg { get; } End Interface Interface IExtendedInterface string ErrorMsg { get; set; } string SomeOtherProperty { get; set; } End Interface I want a class to implement both interfaces: Public Class Foo Implements ISimpleInterface, IExtendedInterface How do I define the ErrorMsg property in the class given that each interface has a

问题 I'm working on a huge project that I didn't start. My task is to add some additional functionality to what already is there. I'm in a situation where I have to use virtual inheritance because I have a diamond model. The situation is depicted in the following illustration: Base class / \ / \ My new class A class that was there before (OldClass) \ / \ / \ / \ / My other new class For this to work, both the classes in the middle have to inherit from the base through public virtual instead of