multiple-inheritance

问题 I'm familiar with the principle (for example, from this answer and this one) that when a class has a move constructor and/or move assignment operator, its default copy constructor and copy assignment operator are deleted. However, In the examples I've seen, this can be addressed by explicitly defining a new copy constructor and assignment operator. In my particular case, I have a class which is derived by joint inheritance from a C-style struct and a template class. The copy and move

问题 We have the following simple (and slightly modified to add main and output) example in the Standard: struct A { virtual void f() { cout << "A\n"; } }; struct B : virtual A { virtual void f() { cout << "B\n"; } }; struct C : B, virtual A { using A::f; }; int main() { C c; c.f(); // calls B​::​f, the final overrider c.C::f(); return 0; } From which we can make a conclusion that using A::f does not present an overrider. But what wording in the Standard dictates it? Here is the wording for the

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 5 years ago . I have a question about name clashes in python. If I have something like: class A: a='a' class B(A): a='b' class C(A): a='c' class D(C,B): pass D.a will print c , is there any way to retrieve B.a from D or A.a ? 回答1: Yes, you can do exactly what you suggest: class D(C, B): a = A.a 来源： https://stackoverflow.com

问题 #include <iostream> using namespace std; struct A{ A() {cout << "A" << endl;} A(int a) {cout << "A+" << endl;} }; struct B : virtual A{ B() : A(1) {cout << "B" << endl;} }; struct C : virtual A{ C() : A(1) {cout << "C" << endl;} }; struct D : virtual A{ D() : A() {cout << "D" << endl;} }; struct E : B, virtual C, D{ E(){cout << "E" << endl;} }; struct F : D, virtual C{ F(){cout << "F" << endl;} }; struct G : E, F{ G() {cout << "G" << endl;} }; int main(){ G g; return 0; } Program prints: A C

问题 I intend this question to be a more generalized question relating to my question found at the following link: Solving design involving multiple inheritance and composite classes in c++ I am working with data sets related to Galaxies. The data about each galaxy will contain information about a galaxie's solar systems, each solar systems planets and each planets moons. The Composite Requirement: From this alone I imagine that I need to use composite class design where I create a class for the

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 5 years ago . Below is a pseudo declaration for a multilevel inheritance. Base class ( protected int data) derived1 : virtual public base ( protected int data1 ) derived2 : virtual public base ( protected int data2) derived3 : derived1,derived2 ( private int data3 ) Main(){ base b; derived1 d1; derived2 d2; derived3 d3; }

问题 Based on this answer, of how __new__ and __init__ are supposed to work in Python, I wrote this code to dynamically define and create a new class and object. class A(object): def __new__(cls): class C(cls, B): pass self = C() return self def foo(self): print 'foo' class B(object): def bar(self): print 'bar' a = A() a.foo() a.bar() Basically, because the __new__ of A returns a dynamically created C that inherits A and B, it should have an attribute bar . Why does C not have a bar attribute? 回答1

问题 I am trying to create a PyQt5.QtWidgets.QWidget derived widget, whilst at the same time inherit from another base class, Base . Inheriting from Base causes an error when calling the QWidget constructor, saying I never provided the arguments which Base requires. This is how I attempt to call the QWidget and Base constructors: class Deriv(QtWidgets.QWidget, Base): def __init__(self): QtWidgets.QWidget.__init__(self) Base.__init__(self, "hello world") The error I'm getting says: QtWidgets

问题 i'm struggling in what would be a good practice or better approach to communicate 'sibling classes in es6' quoted because they haven't a real parent class, by definition. let me explain better: class Car { constructor(typeOfMotor){ this.motor = typeOfMotor; this.mount(); this.addListener(); } mount() { // Some async logic here, and this will return true or false; } addListener(driver) { // Here i want to listen this.mount method and, // when return true, then call the ride method in the

问题 I met an issue when using multi inheritance with PyQt, the Programe 1# source code as below: #!python3 import sys; from PyQt5.QtWidgets import *; from PyQt5.QtGui import *; from PyQt5.QtCore import *; class WP_Widget(QWidget): def __init__(self): print("WP_Widget init"); super().__init__(); class WP_Line(QLineEdit): def __init__(self, text='',*args, **kargs): super().__init__(); self.setText(text); class Widget_C(WP_Widget, WP_Line): #class Widget_C(WP_Line, WP_Widget): def __init__(self):