双向链表

#include <iostream>#include "dlist.h"int main()//测试程序{Dlist<int> dlist;int i=dlist.size();std::cout<<i<<std::endl;dlist.push_back(2);for (int j1=0; j1<dlist.size(); ++j1)std::cout<<dlist.value(j1+1)<<'-';std::cout<<std::endl;dlist.push_front(4);for (int j2=0; j2<dlist.size(); ++j2)std::cout<<dlist.value(j2+1)<<'-';std::cout<<std::endl;dlist.insert_after(7,1);i=dlist.size();std::cout<<i<<std::endl;for (int j3=0; j3<dlist.size(); ++j3)std::cout<<dlist.value(j3+1)<<'-';std::cout<<std::endl;dlist.reverse();std::cout<<dlist.size()<<std::endl;for (int j4=0; j4<dlist.size(); ++j4)std::cout<<dlist.value(j4+1)<<'-';std::cout<<std::endl;dlist.clear();std::cout<<dlist.size()<<std::endl;return 0;}

#ifndef _DLIST_H_INCLUDED        //头文件"dlist.h"#define _DLIST_H_INCLUDED#include <cassert>#include <iostream>template<typename T>struct Dlist_node {T element;Dlist_node* next;Dlist_node* prev;Dlist_node() : element(), next(0), prev(0) {}explicit Dlist_node(const T& elem) : element(elem), next(0), prev(0) {}~Dlist_node() { next=prev=0; }};template<typename T>class Dlist {typedef Dlist_node<T>* Ptrn;public:Dlist();~Dlist();bool empty() const { return hb_size ? false : true; }int size() const { return hb_size; }void reverse();//void sort() const;T value(int pos) const;void push_front(const T& elem);T pop_front();void push_back(const T& elem);T pop_back();void insert_after(const T& elem, int pos);T erase(int pos);void erase(int beg, int end);void clear();private:Dlist_node<T>* hb_head;Dlist_node<T>* hb_tail;int hb_size;Dlist_node<T>* find(int pos) const;T erase(Dlist_node<T>* pSln);};template<typename T>Dlist<T>::Dlist() : hb_head(new Dlist_node<T>),hb_tail(new Dlist_node<T>), hb_size(0){hb_head->next=hb_tail;hb_head->prev=0;hb_tail->prev=hb_head;hb_tail->next=0;}template<typename T>Dlist<T>::~Dlist(){clear();delete hb_head;delete hb_tail;}template<typename T>void Dlist<T>::clear(){if (hb_size != 0)erase(1,hb_size);}template<typename T>Dlist_node<T>* Dlist<T>::find(int pos) const{if (pos<0 || pos>hb_size) {std::cerr<<"error, position out of range!\n";return 0;}Ptrn ptr=hb_head;int i=0;while (i != pos) {ptr=ptr->next;++i;}return ptr;}template<typename T>void Dlist<T>::insert_after(const T& elem, int pos){Ptrn pbef=find(pos);if (0 == pbef) {return;}Ptrn paft=pbef->next;Ptrn pSln=new Dlist_node<T>;pSln->element=elem;pbef->next=pSln;pSln->prev=pbef;paft->prev=pSln;pSln->next=paft;++hb_size;}template<typename T>void Dlist<T>::push_front(const T& elem){insert_after(elem,0);}template<typename T>void Dlist<T>::push_back(const T& elem){insert_after(elem,hb_size);}template<typename T>T Dlist<T>::erase(Dlist_node<T>* pSln){pSln->prev->next=pSln->next;pSln->next->prev=pSln->prev;T t=pSln->element;delete pSln;--hb_size;return t;}template<typename T>T Dlist<T>::erase(int pos){Ptrn pSln=find(pos);assert(pSln != 0);return erase(pSln);}template<typename T>T Dlist<T>::pop_front(){return erase(1);}template<typename T>T Dlist<T>::pop_back(){return erase(hb_size);}template<typename T>void Dlist<T>::erase(int beg, int end){Ptrn pbeg=find(beg);Ptrn pend=find(end);if (0==pbeg || 0==pend) {return;}pbeg->prev->next=pend->next;pend->next->prev=pbeg->prev;Ptrn pstop=pend->next;while (pbeg != pstop) {Ptrn ptm=pbeg;pbeg=pbeg->next;delete ptm;--hb_size;}}template<typename T>T Dlist<T>::value(int pos) const{Ptrn pSln=find(pos);assert(0 != pSln);return pSln->element;}template<typename T>void Dlist<T>::reverse(){Ptrn ptr=hb_head;while (ptr != hb_tail) {ptr->prev=ptr->next;ptr=ptr->next;}ptr=hb_head;while (ptr != hb_tail) {Ptrn pbef=ptr;ptr=ptr->prev;ptr->next=pbef;}Ptrn head=hb_head;hb_head=hb_tail;hb_tail=head;}#endif