multiple-inheritance

问题 I'm trying to access the member variable x in struct Top using a Bottom object. The code is the following: #include <cstdio> struct Top { public: int x = 1; }; struct Left : public Top { int x = 2; }; struct Right : public Top { int x = 3; }; struct Bottom : public Left, public Right { int x = 4; }; int main() { Bottom b; std::printf("value: %d\n", b.Left::Top::x); return 0; } This gives the following error using gcc 4.8: main.cpp: In function 'int main()': main.cpp:27:45: error: 'Top' is an

问题 I'm trying to access the member variable x in struct Top using a Bottom object. The code is the following: #include <cstdio> struct Top { public: int x = 1; }; struct Left : public Top { int x = 2; }; struct Right : public Top { int x = 3; }; struct Bottom : public Left, public Right { int x = 4; }; int main() { Bottom b; std::printf("value: %d\n", b.Left::Top::x); return 0; } This gives the following error using gcc 4.8: main.cpp: In function 'int main()': main.cpp:27:45: error: 'Top' is an

问题 I'm trying to access the member variable x in struct Top using a Bottom object. The code is the following: #include <cstdio> struct Top { public: int x = 1; }; struct Left : public Top { int x = 2; }; struct Right : public Top { int x = 3; }; struct Bottom : public Left, public Right { int x = 4; }; int main() { Bottom b; std::printf("value: %d\n", b.Left::Top::x); return 0; } This gives the following error using gcc 4.8: main.cpp: In function 'int main()': main.cpp:27:45: error: 'Top' is an

问题 I was wondering if a C# extension method of some class could act as an implementation of interface? What do I have: An iterface: public interface IEventHandler { void Notify(SEvent ev, IEventEmmiter source); } A class that implements it: class Sim : IEventHandler { /*public void Notify(SEvent ev, IEventEmmiter source) { Console.WriteLine("Got notified: " + ev.Name); }*/ } And a class that contains the extension method: public static class ReflectiveEventDispatcher { public static void Notify

问题 I was wondering if a C# extension method of some class could act as an implementation of interface? What do I have: An iterface: public interface IEventHandler { void Notify(SEvent ev, IEventEmmiter source); } A class that implements it: class Sim : IEventHandler { /*public void Notify(SEvent ev, IEventEmmiter source) { Console.WriteLine("Got notified: " + ev.Name); }*/ } And a class that contains the extension method: public static class ReflectiveEventDispatcher { public static void Notify

问题 I have my Scala classes structured as below: trait ActualClass extends ParentClass { override def method1(inputStr:String):String = { "actual "+ inputStr } def execute():String = { this.method1("test") } } trait WithClass extends ParentClass { override def method1(inputStr:String):String = { "with "+ inputStr } } class ParentClass { def method1(inputStr:String):String = { "parent "+ inputStr } } object TestClass extends App{ val actualClass = new ActualClass with WithClass { } println

问题 I've got a real situation which can be summarized in the following example: template< typename ListenerType > struct Notifier { void add_listener( ListenerType& ){} }; struct TimeListener{ }; struct SpaceListener{ }; struct A : public Notifier< TimeListener > , public Notifier< SpaceListener > { }; struct B : TimeListener{ }; int main() { A a; B b; a.add_listener( b ); // why is ambiguous? return 0; } Why is not obvious to the compiler that B is a TimeListener , and therefore the only

问题 A very simple case of diamond-type inheritance: class Root: def f(self): print('Root') class A(Root): pass class B(Root): def f(self): print('B') class AB(A, B): pass AB().f() According to Python 3.1.2 documentation: For most purposes, in the simplest cases, you can think of the search for attributes inherited from a parent class as depth-first, left-to-right, not searching twice in the same class where there is an overlap in the hierarchy. Hence, I expect my example to resolve in the order:

问题 A very simple case of diamond-type inheritance: class Root: def f(self): print('Root') class A(Root): pass class B(Root): def f(self): print('B') class AB(A, B): pass AB().f() According to Python 3.1.2 documentation: For most purposes, in the simplest cases, you can think of the search for attributes inherited from a parent class as depth-first, left-to-right, not searching twice in the same class where there is an overlap in the hierarchy. Hence, I expect my example to resolve in the order:

问题 Consider this (completely non-nonsensical, but perfectly valid) class inheritance: struct Area { int size; }; struct Pattern { int size; }; struct R : Area, Pattern {}; struct C : Area, Pattern {}; struct X: R , C {}; Let's see a graph of this great hierarchy: Area Pattern |\ /| | \/ | | /\ | |/ \| R C \ / \/ X Now, if I am not mistaken, X should have 4 size members. How to refer to them using the scope operator? The obvious solution doesn't work: X x; x.R::Area::size = 24; clang error: 23 :