雙向鏈表的C++實現

轉載註明出處http://blog.csdn.net/hongkangwl/article/details/22286469

首先定義節點的結構

struct node {int date;node* prev;node* next;};

老樣子，建立雙鏈表的類

class doublelink{public:int doublelink_insert(doublelink* ptr,int position,int member);int doublelink_erase(doublelink* ptr, int position);void doublelink_display(doublelink* ptr, int num);int doublelink_getlength(doublelink* ptr);doublelink(){root = new node;root->prev = NULL;root->next = NULL;length = 0;}protected:private:int length;node* root;};

插入元素

int doublelink::doublelink_insert(doublelink *ptr, int position, int member){node* nodeinsert = new node;nodeinsert->date = member;if (ptr->doublelink_getlength(ptr) == 0){root->next = nodeinsert;nodeinsert->prev = nodeinsert;nodeinsert->next = nodeinsert;ptr->length++;return 0;} else{if (position == 0){/*root->next->prev = nodeinsert;nodeinsert->prev = root->next->prev;nodeinsert->next = root->next;root->next->prev = nodeinsert;*/nodeinsert->prev = root->next->prev;nodeinsert->next = root->next;root->next->prev->next = nodeinsert;root->next->prev = nodeinsert;root->next = nodeinsert;ptr->length++;return 0;} else{node* current =  root->next;for (int i = 0; i < position; i++){current = current->next;}nodeinsert->next = current;nodeinsert->prev = current->prev;current->prev->next = nodeinsert;//nodeinsert->next = nodeinsert;current->prev = nodeinsert;ptr->length++;return 0;}}}

刪除一個元素，注意0位置上的

int doublelink::doublelink_erase(doublelink* ptr, int position){if (ptr->doublelink_getlength(ptr) == 0){cout<<"鏈表為空白，oop。。"<<endl;return 0;} else{if (ptr->doublelink_getlength(ptr) == 1){ptr->root->next = NULL;ptr->length--;} else{node* deletenode = root->next;for (int i = 0 ; i < position; i++){deletenode = deletenode->next;}deletenode->prev->next = deletenode->next;deletenode->next->prev = deletenode->prev;delete deletenode;ptr->length--;}}}

完整實現代碼和測試結果

#include <iostream>using namespace std;struct node {int date;node* prev;node* next;};class doublelink{public:int doublelink_insert(doublelink* ptr,int position,int member);int doublelink_erase(doublelink* ptr, int position);void doublelink_display(doublelink* ptr, int num);int doublelink_getlength(doublelink* ptr);doublelink(){root = new node;root->prev = NULL;root->next = NULL;length = 0;}protected:private:int length;node* root;};int doublelink::doublelink_erase(doublelink* ptr, int position){if (ptr->doublelink_getlength(ptr) == 0){cout<<"鏈表為空白，oop。。"<<endl;return 0;} else{if (ptr->doublelink_getlength(ptr) == 1){ptr->root->next = NULL;ptr->length--;} else{node* deletenode = root->next;for (int i = 0 ; i < position; i++){deletenode = deletenode->next;}deletenode->prev->next = deletenode->next;deletenode->next->prev = deletenode->prev;delete deletenode;ptr->length--;}}}void doublelink::doublelink_display(doublelink* ptr, int num){node* current = root->next;for (int i = 0; i < num; i++){cout<<current->date<<" ";current = current->next;}cout<<endl;}int doublelink::doublelink_getlength(doublelink* ptr){return ptr->length;}int doublelink::doublelink_insert(doublelink *ptr, int position, int member){node* nodeinsert = new node;nodeinsert->date = member;if (ptr->doublelink_getlength(ptr) == 0){root->next = nodeinsert;nodeinsert->prev = nodeinsert;nodeinsert->next = nodeinsert;ptr->length++;return 0;} else{if (position == 0){/*root->next->prev = nodeinsert;nodeinsert->prev = root->next->prev;nodeinsert->next = root->next;root->next->prev = nodeinsert;*/nodeinsert->prev = root->next->prev;nodeinsert->next = root->next;root->next->prev->next = nodeinsert;root->next->prev = nodeinsert;root->next = nodeinsert;ptr->length++;return 0;} else{node* current =  root->next;for (int i = 0; i < position; i++){current = current->next;}nodeinsert->next = current;nodeinsert->prev = current->prev;current->prev->next = nodeinsert;//nodeinsert->next = nodeinsert;current->prev = nodeinsert;ptr->length++;return 0;}}}int main(){doublelink* doublelink_ptr = new doublelink;for (int i = 0; i < 10; i++){doublelink_ptr->doublelink_insert(doublelink_ptr,0,i);}doublelink_ptr->doublelink_display(doublelink_ptr,20);doublelink_ptr->doublelink_erase(doublelink_ptr,2);doublelink_ptr->doublelink_display(doublelink_ptr,20);return 0;}

測試正確~~