C ++界面风格编程。需要出路
template <typename T>
class BaseQueue
{
public :
virtual void push_back(T value) = 0;
//other virtual methods
};
template <typename T>
class BaseDeque: public virtual BaseQueue<T>
{
public:
virtual void push_front(T value) = 0;
//other virtual methods
};
//Realisation
template <typename T>
class VectorQueue: public BaseQueue<T>
{
typedef typename std::vector<T> array;
private: array adata;
public:
VectorQueue()
{
adata = array();
}
void push_back(T value)
{
adata.push_back(value);
}
};
template <typename T>
class VectorDeque: virtual public VectorQueue<T>, virtual protected BaseDeque<T>//,
{
void push_front(T value)
{
VectorQueue::adata.push_front(value);
}
};
int _tmain(int argc, _TCHAR* argv[])
{
VectorDeque<int> vd = VectorDeque<int>();//here is a error
int i;
std::cin >> i;
return 0;
}
template <typename T>
class VectorDeque: virtual public VectorQueue<T>, virtual protected BaseDeque<T>//,
{
void push_front(T value)
{
VectorQueue::adata.push_front(value);
}
void push_back(T value)
{
VectorQueue::push_back(value);
}
//repeat it fo every virtual method of BaseQueue class (interface)
};
没有找到相关结果
已邀请:
3 个回复
目浆搽
的未在继承链的侧实现，因此最后一个类仍然是抽象的。 我想你在这里强迫一个不应该存在的阶级关系。请注意标准库中的和是不同的容器类型，例如使这些容器适应非常精确的接口而不是尝试继承。砷竣阿
template <typename T> class VectorQueue: public BaseQueue<T> { typedef typename std::vector<T> array; private: array adata; // if this is private, VectorDeque can't reach it public: // constructors have an initializer section // member variables should be initialized there, not in the body VectorQueue() // : adata() // however, no need to explicitly call default constructor { // adata = array(); } }; template <typename T> class VectorDeque: virtual public VectorQueue<T>, virtual protected BaseDeque<T> { void push_front(T value) { // if adata is protected, you can just access it. No need for scoping /*VectorQueue::*/ adata.push_front(value); // Error: std::vector doesn't have a method push_front. // Perhaps you meant to use std::list? } };乏摩纶誊伟
// Abstract bases template <typename T, typename Val> class BaseQueue { public : void push_back(Val val) { static_cast<T*>(this)->push_back(val); } // ... }; template <typename T, typename Val> class BaseDeque { public: void push_front(Val val) { static_cast<T*>(this)->push_front(val); } // ... }; // Concrete class #include <deque> template <typename Val> class QueueDeque: public BaseQueue<QueueDeque<Val>, Val>, public BaseDeque<QueueDeque<Val>, Val> { std::deque<Val> vals; public: void push_front(Val val) { vals.push_front(val); } void push_back(Val val) { vals.push_back(val); } // etc.. }; int main() { QueueDeque<int> vd;// no more error vd.push_front(5); vd.push_back(0); return 0; }