直接上代码,亲测有用。
#ifndef __DLINK_H__ #define __DLINK_H__ /* [phead] -> [index0] -> [index1] -> [index2] -> ...... [phead] [phead] <- [index0] <- [index1] <- [index2] <- ...... [phead] phead 不存储数据。 index是从0开始的。count = index + 1; */ template <class T> struct node { public: node(){} node(T a, node *p1, node *p2) { this->data = a; this->next = p2; this->prev = p1; } node *next; node *prev; T data; }; template <class T> class Dlink { public: Dlink(); ~Dlink(); int create_Dlink(); int destroy_Dlink(); int getCount(); int insert_Dlink(int index, T tData); int insert_Dlink_first(T tData); int insert_Dlink_last(T tData); T get_Dlink(int index); T get_Dlink_first(); T get_Dlink_last(); int delete_Dlink(int index); int delete_Dlink_first(); int delete_Dlink_last(); private: node<T> *get_node(int index); node<T> *m_pHead; int m_nCount; }; template <class T> Dlink<T>::Dlink() { m_pHead = NULL; m_nCount = 0; } template <class T> Dlink<T>::~Dlink() { } template <class T> node<T> *Dlink<T>::get_node(int index) { if(index < 0 || index >= m_nCount) { cout << __FUNCTION__ << "() Error" << endl; return NULL; } #if 0 node<T> *pnode = m_pHead->next; int i = 0; while(i < m_nCount) { if(i == index) { return pnode; } pnode = pnode->next; i++; } #else // 正向查找 if(index <= m_nCount/2) { int i = 0; node<T> *pnode = m_pHead->next; while(i <= m_nCount/2) { if(i == index) { return pnode; } pnode = pnode->next; i++; } } else // 反向查找 { node<T> *pnode = m_pHead->prev; int i = m_nCount - 1; // 注意这里是必须要减一。因为m_nCount = index + 1; while(i > (m_nCount/2)) { if(i == index) { return pnode; } pnode = pnode->prev; i--; } } #endif return NULL; } template <class T> int Dlink<T>::create_Dlink() { m_pHead = new node<T>(); m_pHead->next = m_pHead->prev = m_pHead; // 这个初始化非常重要 return 0; } template <class T> int Dlink<T>::destroy_Dlink() { if(!m_pHead) { cout << __FUNCTION__ << "() Error" << endl; return -1; } node<T> *pnode = m_pHead->next; node<T> *tmp; while(pnode != m_pHead) { tmp = pnode; pnode = pnode->next; delete tmp; tmp = NULL; } delete m_pHead; m_pHead = NULL; m_nCount = 0; return 0; } template <class T> int Dlink<T>::getCount() { return m_nCount; } // index 表示要插入后的位置,所以这里可以等于m_nCount。表示在最后一个 template <class T> int Dlink<T>::insert_Dlink(int index, T tData) { if(!m_pHead) { cout << __FUNCTION__ << "() Error" << endl; return -1; } if(index < 0 || index > m_nCount) { cout << __FUNCTION__ << "() Error" << endl; return -1; } if(index == 0) { return insert_Dlink_first(tData); } if(index == m_nCount) { return insert_Dlink_last(tData); } node<T> *pindex = get_node(index); node<T> *pnode = new node<T>(tData, pindex->prev, pindex); pindex->prev->next = pnode;
#if 0 // 20180223 update. 突然发现这里写错了 pindex->next->prev = pnode;
#endif
pindex->prev = pnode; // 改为这样
m_nCount++; return 0; } template <class T> int Dlink<T>::insert_Dlink_first(T tData) { if(!m_pHead) { cout << __FUNCTION__ << "() Error" << endl; return -1; } node<T> *pnode = new node<T>(tData, m_pHead, m_pHead->next); if(!pnode) { cout << __FUNCTION__ << "() Error step1 " << endl; return -1; } m_pHead->next->prev = pnode; m_pHead->next = pnode; m_nCount++; return 0; } template <class T> int Dlink<T>::insert_Dlink_last(T tData) { if(!m_pHead) { cout << __FUNCTION__ << "() Error" << endl; return -1; } node<T> *pnode = new node<T>(tData, m_pHead->prev, m_pHead); if(!pnode) { cout << __FUNCTION__ << "() Error step1 " << endl; return -1; } m_pHead->prev->next = pnode; m_pHead->prev = pnode; m_nCount++; return 0; } template <class T> T Dlink<T>::get_Dlink(int index) { node<T> *pnode = get_node(index); if(!pnode) { cout << __FUNCTION__ << "() Error" << endl; return NULL; } return pnode->data; } template <class T> T Dlink<T>::get_Dlink_first() { return get_Dlink(0); } template <class T> T Dlink<T>::get_Dlink_last() { return get_Dlink(count - 1); } // index 是从0开始编号的。这里的范围是 0 -- m_nCount-1 template <class T> int Dlink<T>::delete_Dlink(int index) { if(index < 0 || index >= m_nCount) { cout << __FUNCTION__ << "() Error" << endl; return -1; } node<T> *pnode = get_node(index); if(pnode) { pnode->next->prev = pnode->prev; pnode->prev->next = pnode->next; delete pnode; pnode = NULL; m_nCount--; } return -1; } template <class T> int Dlink<T>::delete_Dlink_first() { return delete_Dlink(0); } template <class T> int Dlink<T>::delete_Dlink_last() { return delete_Dlink(m_nCount - 1); } #endif // __DLINK_H__
测试:
#include<iostream> #include"dlink.h" using namespace std; void fun1() { cout << "fun1() +++" << endl; /* // node test node<int> *p1 = (node<int>*)malloc(sizeof(node<int>)); p1->data = 33; cout << "data = " << p1->data << endl; node<int> p; p.data = 30; */ Dlink<int> *pDlink = new Dlink<int>; pDlink->create_Dlink(); int arr[5] = {11, 22, 33, 44, 55}; for(int i = 0; i < 5; i++) { pDlink->insert_Dlink(0, arr[i]); // pDlink->insert_Dlink_last(arr[i]); } pDlink->insert_Dlink(5, 4444); // pDlink->delete_Dlink(1); // pDlink->destroy_Dlink(); int count = pDlink->getCount(); cout << "fun1() count:" << count << endl; for(int i = 0; i < count; i++) { int data = pDlink->get_Dlink(i); cout << "index:" << i << " - data:" << data << endl;; } cout << "fun1() ---" << endl; } int main() { cout << "main() +++" << endl; fun1(); cout << "main() ---" << endl; return 0; }
关于为何C++的模板类声明和实现要放在一起可以参考:http://www.cnblogs.com/xcywt/p/8039574.html