multiple-inheritance

问题 This question already has answers here : Java : If A extends B and B extends Object, is that multiple inheritance (11 answers) Closed 4 years ago . Class Object is the root of class hierarchy. Every class has Object as a superclass. So, if I am extending a API class, will it be like, multiple inheritance? Obviously, Java doesn't support multiple inheritance. How does it then work? 回答1: Superclass is not the same thing as parent class. You can only have one mother, but you have a much larger

问题 I want a string with one additional attribute, let's say whether to print it in red or green. Subclassing(str) does not work, as it is immutable. I see the value, but it can be annoying. Can multiple inheritence help? I never used that. Inheriting only object and using self.value=str means I have to implement all string-ness messages (like strip) myself. Or is there a way to forward them, like Ruby's missing_method? I think using a class-level dictionary indexed by instance to store the color

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed last year . To be clear, I'm not asking if/why multiple inheritance is good or bad. I've heard a lot of arguments from both sides of that debate. I'm wondering if there is any kind of design problem or scenario in C++ in which multiple inheritance is either the only way to accomplish something,

问题 Why is it that in the code below the compiler complains that PureAbstractBase is an ambiguous base class of MultiplyInheritedClass ? I realize I have two copies of the PureAbstractBase in MultiplyInheritedClass and that FirstConreteClass and SecondConreteClass should be derived virtually because they're the middle row of the diamond (and that does indeed fix the problem with the code below). But even though I have two copies of the interface why is it that the code in MultiplyInheritedClass

问题 I refer to the following as “multiple re-inheritance”: inheriting a class once directly and one or more times indirectly by inheriting one or more of its descendants inheriting a class indirectly two or more times by inheriting two or more of its descendants I want to know if it exists and how to unambiguously access embedded subobjects. 1.) [ Professional C++ , 2 nd ed.] † states a compilable program can't have a class that directly inherits both its immediate parent and said parent's parent

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: What is the exact problem with multiple inheritance? Why is multiple inheritance considered to be evil while implementing multiple interfaces is not? Especially when once considers that interfaces are simply pure abstract classes? (More or less) duplicate of What is the exact problem with multiple inheritance?, Multiple Inheritance in C#, and some others... 回答1: The common problem with multiple inheritance is

问题 In English, a homograph pair is two words that have the same spelling but different meanings. In software engineering, a pair of homographic methods is two methods with the same name but different requirements. Let's see a contrived example to make the question as clear as possible: interface I1 { /** return 1 */ int f() } interface I2 { /** return 2*/ int f() } interface I12 extends I1, I2 {} How can I implement I12 ? C# has a way to do this, but Java doesn't. So the only way around is a

问题 I am trying to make sense of the statement in book effective c++. Following is the inheritance diagram for multiple inheritance. Now the book says separate memory in each class is required for vptr. Also it makes following statement An oddity in the above diagram is that there are only three vptrs even though four classes are involved. Implementations are free to generate four vptrs if they like, but three suffice (it turns out that B and D can share a vptr), and most implementations take

问题 I understand the basics of C++ virtual inheritance. However, I'm confused about where exactly I need to use the virtual keyword with a complex class hierarchy. For example, suppose I have the following classes: A / \ B C / \ / \ D E F \ / \ / G H \ / I If I want to ensure that none of the classes appear more than once in any of the subclasses, which base classes need to be marked virtual ? All of them? Or is it sufficient to use it only on those classes that derive directly from a class that

问题 in a multiple inheritance setting such as laid out in, how can I use super() and also handle the case when the signature of the function changes between classes in the hierarchy? i.e. can I rewrite this example (in python3) to work with super() ? example was taken from the article super() considered harmful article class A(): def __init__(self): print("A") class B(object): def __init__(self): print("B") class C(A): def __init__(self, arg): print("C","arg=",arg) A.__init__(self) class D(B):