双队列草稿

 #ifndef DDEQUE_H #define DDEQUE_H #include "iostream" #include "cstddef" #include "memory" using namespace std; template<typename T> class ddeque { private: class iterator { public: iterator(){} iterator(T* p, T** pp, bool direction) //direction==0向上，direction==1向下 { if (direction) { first = p; current = p; last = p+20; node = pp; } else { first = p; current = p+20; last = p+20; node = pp; } } void setIter(T* p, T** pp, bool direction) //direction==0向上，direction==1向下 { if (direction) { first = p; current = p; last = p+20; node = pp; } else { first = p; current = p+20; last = p+20; node = pp; } } iterator operator++(int) { iterator itemp = *this; ++current; return itemp; } iterator operator++() { ++current; return *this; } iterator operator--(int) { iterator itemp = *this; --current; return itemp; } iterator operator--() { --current; return *this; } iterator* operator->() { return this; } /*T operator*() { return *(this->current); //////////////////////////////////////////////////////////左值问题 }*/ T* first; T* current; T* last; T** node; }; public: ddeque() { pindex = new T*[50]; upindex = pindex+24; downindex = pindex+25; pdata = new T[20]; *upindex = pdata; upiter.setIter(pdata,upindex,false); pdata = new T[20]; *downindex = pdata; downiter.setIter(pdata,downindex,true); length = 0; uplength = 0; downlength = 0; } ddeque(const ddeque&){} ddeque& operator=(const ddeque&){} ~ddeque(){} size_t size() { return length; } bool empty() { return length == 0; } void push_back(T x) { if (end().current == end().last) { pdata = new T[20]; ++downindex; *downindex = pdata; downiter.setIter(pdata,downindex,true); } *(downiter.current) = x; ////////////////////////////////////////////////////////////////////////// ++downiter; ++length; ++downlength; } void pop_back() { ///destroy(end().current); (end().current)->~T(); --end().current; --length; --downlength; if (end().current == end().first) { delete end().first; --downindex; downiter.setIter(*downindex,downindex,false); //已满，current == last } } void push_front(T x) { if (begin().current == begin().first) { pdata = new T[20]; --upindex; *upindex = pdata; upiter.setIter(pdata,upindex,false); } //--upiter.current; --upiter; *(upiter.current) = x; ////////////////////////////////////////////////////////////////////////// ++length; ++uplength; } void pop_front() { //destroy(begin().current); (begin().current)->~T(); //++begin().current; ++begin(); --length; --uplength; if (begin().current == begin().last) { delete begin().first; ++upindex; upiter.setIter(*upindex,upindex,true); //已满，current == first } } iterator& begin() { return upiter; } iterator& end() { return downiter; } void clear() { while (uplength--) { pop_front(); } while (downlength--) { pop_back(); } } friend ostream& operator<<(ostream& os, ddeque<T>& deq) { T** index = deq.upindex; T* p = *index; iterator iter; os<<"< "; while (deq.begin().current != deq.begin().last) { os<<*((deq.begin()).current)<<" "; ++(deq.begin()); } cout<<endl; ++index; while (index != deq.downindex) { iter.setIter(p,index,true); //current == first for (;iter.current!=iter.last; ++iter) { os<<*(iter->current)<<" "; } os<<endl; ++index; p = *index; } for (T* t= deq.end().first; t!=deq.end().current; ++t ) { os<<*t<<" "; } os<<" >"<<endl; return os; } private: size_t length; size_t uplength; size_t downlength; T** pindex; T** upindex; T** downindex; iterator upiter; iterator downiter; T* pdata; }; #endif