问题描述
好的。我不是很好的多态性在C + +,但我现在有一个问题。想象这些类:
OK. I'm not very good at polymorphism in C++, but I've a problem now. Imagine these classes:
class Parent {
public:
Parent();
virtual ~Parent();
};
class Child : public Parent
{
public:
Child();
};
class Director
public:
Director();
void doStuff(Parent* p);
};
// Assume we have a instance of Director, and call the doStuff function here:
doStuff(new Child()); // Gives error
我得到错误
无法将参数1从Child *转换为Parent *
是,为什么这不工作?
我需要做任何类型的铸造或什么,或什么是问题?
And my simple question is, WHY this doesn't work?Do I need to do any sort of casting or what, or what is the problem?
EDIT:
我把所有的文件在这里,因为他们是。
我认为问题在于我的包含,因为我真的不知道如何应该用#ifndef和这样做。请检查出来。
Director.h:
Director.cpp:
IApp.h:
IApp.cpp:
IScene:h:
IScene.cpp:
I put all my files here as they are.I think the problem lies in my inclusions, since I really dont have any idea of how it's supposed to be done with #ifndef and such. Please check them out.
Director.h: http://pastebin.com/2uJqezju
Director.cpp: http://pastebin.com/SZ6cuBJC
IApp.h: http://pastebin.com/euCAwpnL
IApp.cpp: http://pastebin.com/JHDuQUhW
IScene:h: http://pastebin.com/cweH9G6p
IScene.cpp: http://pastebin.com/9epW0dRA
然后我已创建了一些实例:
GameApp.h(继承EDGE :: IApp):
GameApp.cpp:
GameScene.h(继承EDGE :: IScene):
GameScene.cpp:
Then I have created some instances of it:
GameApp.h (inherits EDGE::IApp): http://pastebin.com/QbjbVqSi
GameApp.cpp: http://pastebin.com/sYJvmbeP
GameScene.h (inherits EDGE::IScene): http://pastebin.com/K1WYNvRf
GameScene.cpp: http://pastebin.com/uJx3FLBW
不要害怕检查它们,实际上每行中有10行代码他们。但问题是在GameApp.cpp中,我尝试创建一个GameScene的实例,并将其传递给Director-> createNewScene(IScene * scene)。
Don't be afraid to check them out, there are really like 10 lines of code in each of them. But the problem is in GameApp.cpp where I try to create an instance of GameScene, and pass it to the Director->createNewScene(IScene* scene).
推荐答案
Director.h:
Director.h:
class IScene;
应在命名空间内
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