C/C++——单链表的主要功能实现

  1 /****************************
  2  * 单链表
  3  * Author: 玉做的树
  4  *
  5  * Node* create() 根据输入创建链表
  6  * Node* create(int []) 根据数组创建链表
  7  * const int length(Node *head) 测长
  8  * void print(Node* head) 输出链表
  9  * Node* push_back(Node* head, int _data) 尾插入
 10  * Node* push_front(Node* &head, int _data) 首插入
 11  * Node* insert(Node* head, int _data, int pos) 特定位置插入
 12  * void remove(Node** head, int _data) 删除特定值的元素
 13  * void erase(Node **head, int pos) 删除特定位置的元素
 14  * Node* sort(Node* head) 排序
 15  *
 16  */
 17 
 18 #include <iostream>
 19 
 20 using namespace std;
 21 
 22 struct Node {
 23     int data;
 24     Node *next;
 25     Node() {
 26         data = 0;
 27         next = NULL;
 28     }
 29     Node(int _data) {
 30         data = _data;
 31         next = NULL;
 32     }
 33 };
 34 
 35 // 根据输入创表
 36 Node* create() {
 37     Node *head, *p1, *p2;
 38     int _data;
 39     head = new Node();
 40     p1 = head;
 41     
 42     cout << "Please Input data with space and end with EOF:\n";
 43     while (cin >> _data) {
 44         p2 = new Node(_data);
 45         p1->next = p2;
 46         p1 = p2;
 47     }
 48     head = head->next; // 这一步是为了消除头指针未合理利用
 49     return head;
 50 }
 51 
 52 // 根据数组创表
 53 Node* create(int elements[], int len) {
 54     Node *head, *p1, *p2;
 55     head = new Node();
 56     p1 = head;
 57     
 58     for (int i = 0; i < len; i++) {
 59         p2 = new Node(elements[i]);
 60         p1->next = p2;
 61         p1 = p2;
 62     }
 63     head = head->next; // 这一步是为了消除头指针未合理利用
 64     return head;
 65 }
 66 
 67 // 测长
 68 const int length(Node *head) {
 69     int len = 0;
 70     Node* tmp = head;
 71     while (tmp != NULL) {
 72         tmp = tmp->next;
 73         len++;
 74     }
 75     return len;
 76 }
 77 
 78 // 输出
 79 void print(Node* head) {
 80     if (head == NULL) {
 81         cout << "The List is empty!\n";
 82         return;
 83     }
 84     int len = length(head);
 85     Node* tmp = head;
 86     cout << "The length of the List is " << len << endl;
 87     
 88     while (tmp != NULL) {
 89         cout << tmp->data << " ";
 90         tmp = tmp->next;
 91     }
 92     cout << endl;
 93 }
 94 
 95 // 尾插入
 96 Node* push_back(Node* head, int _data) {
 97     Node *tmp, *tmp2, *newNode;
 98     tmp = tmp2 = head;
 99     while (tmp != NULL) {
100         tmp2 = tmp; // tmp2用于记录原链表最后一个节点，因为tmp最后指向空，已经不是末尾节点
101         tmp = tmp->next;
102     }
103     newNode = new Node(_data);
104     tmp2->next = newNode;
105     return newNode;
106 }
107 
108 // 头插入, 修改指针要用 ** 或 *&
109 Node* push_front(Node* &head, int _data) {
110     /*       * * 用法
111     Node *newNode = new Node(_data);
112     newNode->next = *head;
113     *head = newNode;
114      */
115     
116     //       * &用法
117     Node *newNode = new Node(_data);
118     newNode->next = head;
119     head = newNode;
120     return newNode;
121 }
122 
123 // 按position插入
124 Node* insert(Node* head, int _data, int pos) {
125     if (pos < 0 || pos > length(head)) {
126         return NULL;
127     }
128     int count = 0;
129     Node* tmp, *tmp2, *newNode;
130     tmp = tmp2 = head;
131     newNode = new Node(_data);
132     while (tmp != NULL && count++ != pos) {
133         tmp2 = tmp; // previous one
134         tmp = tmp->next;
135     }
136     if (tmp == head) {
137         push_front(head, _data);
138     } else if (tmp == NULL) {
139         push_back(head, _data);
140     } else {
141         tmp2->next = newNode;
142         newNode->next = tmp;
143     }
144     return newNode;
145 }
146 
147 // 删除所有指定元素
148 void remove(Node** head, int _data) {
149     Node* tmp = *head, *tmp2;
150     // 先处理麻烦的头结点
151     if (*head != NULL && (*head)->data == _data) {
152         *head = (*head)->next;
153     }
154     while (tmp->next != NULL) {
155         tmp2 = tmp;
156         tmp = tmp->next;
157         if (tmp->data == _data) {
158             tmp2->next = tmp->next;
159         }
160         tmp = tmp2->next;
161     }
162 }
163 
164 // 删除特定position元素
165 void erase(Node **head, int pos) {
166     Node* tmp = *head, *tmp2 = tmp;
167     
168     if (pos < 0 || pos > length(*head)) {
169         return;
170     }
171     if (pos == 0 && *head != NULL) {
172         *head = (*head)->next;
173         delete tmp;
174         return;
175     }
176     while (tmp->next != NULL && pos--) {
177         tmp2 = tmp;
178         tmp = tmp->next;
179     }
180     tmp2->next = tmp->next;
181     delete tmp;
182 }
183 
184 // 排序
185 Node* sort(Node* head) {
186     int len = length(head);
187     Node* tmp;
188     if (head == NULL || head->next == NULL)
189         return head;
190     
191     for (int i = 0; i < len; i++) {
192         tmp = head;
193         for (int j = 0; j < len - i - 1; j++) {
194             if (tmp->data > tmp->next->data) {
195                 tmp->data = tmp->data + tmp->next->data;
196                 tmp->next->data = tmp->data - tmp->next->data;
197                 tmp->data = tmp->data - tmp->next->data;
198             }
199             tmp = tmp->next;
200         }
201     }
202     return head;
203 }
204 
205 int main() {
206     int a[] = {3, 7, 3, 4, 1, 6};
207     Node* list = create(a, 6);
208     print(list);
209     
210     sort(list);
211     print(list);
212     
213     /*
214     push_back(list, 7);
215     print(list);
216 
217     push_front(list, 0); // *&用法
218     print(list);
219     
220     insert(list, 2, 1);
221     print(list);
222     
223     remove(&list, 2); // 删除特定值, **用法
224     print(list);
225     
226     erase(&list, 0);
227     print(list);
228      */
229     
230     return 0;
231 }