1 问题

用C语言实现链表

 

 

 

2 代码实现

#include <stdio.h>
#include <stdlib.h>#define true 0
#define false -1typedef struct Node
{int value;struct Node *next;
} List;/***初始化链表*/
struct Node* init_list()
{struct Node *head = (struct Node*)malloc(sizeof(struct Node));if (head){head->next = NULL;return head;}return NULL;
}/**创建节点*/
struct Node* create_node(int value)
{struct Node *node = (struct Node*)malloc(sizeof(struct Node));if (node){node->value = value;return node;}return NULL;
}/**第一种方法插入节点*/
int insert_list(struct Node **head, List* node)
{if (*head == NULL || node == NULL){printf("head or node is NULL");return false;}node->next = *head;*head = node;return true;
}/**第二种方法插入节点*/
int insert_list1(struct Node *head, List* node)
{if (head == NULL || node == NULL){printf("head or node is NULL");return false;}node->next = head->next;head->next = node;return true;
}/**第一种方法打印*/
void print_list(List *head)
{if (head == NULL){printf("head is NULL\n");return;	}while (head->next != NULL){printf("value is %d\n", head->value);head = head->next;}
}/**第二种方法打印*/
void print_list1(List *head)
{if (head == NULL){printf("head is NULL\n");return;	}struct Node *p = head->next;while (p != NULL){printf("value is %d\n", p->value);p = p->next;	}}/**更具这个值能否能到节点*/
struct Node* get_node(List *head, int value)
{if (head == NULL)return NULL;struct Node *p = head;while (p != NULL){if (p->value == value){return p;	}p = p->next;	}return NULL;	
}/**第一种方法删除节点*/
int delete_node(struct Node **head, struct Node *node)
{if (*head == NULL)return false;if ((*head) == node){*head = (*head)->next;return true;}struct Node *p = *head;while ((*head)->next != NULL){	if ((*head)->next == node){	(*head)->next =(*head)->next->next;*head = p;return true;}*head = (*head)->next;}*head = p;return false;
}/**第二种方法删除节点*/
int delete_node1(struct Node *head, struct Node *node)
{if (head == NULL)return false;while (head->next != NULL){if (head->next == node){head->next = head->next->next;return true;}head = head->next;}return false;
}/**释放链表*/
int free_list(List *head)
{if (head == NULL)return false;struct Node *p = NULL;while(head != NULL){p = head;head = head->next;	free(p);}return true;
}int main()
{struct Node* head = NULL;struct Node* node1 = NULL, *node2 = NULL, *node3 = NULL;struct Node* node4 = NULL, *node5 = NULL, *node6 = NULL;head = init_list();if (!head){printf("init head fail\n");	}node1 = create_node(5);node2 = create_node(4);node3 = create_node(3);node4 = create_node(2);node5 = create_node(1);node6 = create_node(3);insert_list1(head, node1);insert_list1(head, node2);insert_list1(head, node3);insert_list1(head, node4);insert_list1(head, node5);insert_list1(head, node6);print_list1(head);printf("first print_list---------------\n");delete_node1(head, node1);print_list1(head);printf("second print_list--------------\n");free_list(head);head = NULL;head = init_list();if (!head){printf("init head fail\n");	}node1 = create_node(5);node2 = create_node(4);node3 = create_node(3);node4 = create_node(2);node5 = create_node(1);node6 = create_node(3);insert_list(&head, node1);insert_list(&head, node2);insert_list(&head, node3);insert_list(&head, node4);insert_list(&head, node5);insert_list(&head, node6);print_list(head);printf("third print_list---------------\n");delete_node(&head, node4);print_list(head);printf("four print_list---------------\n");struct Node *result = get_node(head, 4);if (result){printf("list contain node and the value of node is %d\n", result->value);}else{printf("list do not contain the node\n");	}free_list(head);head = NULL;return 0;	
}

 

 

 

3 运行结果

value is 3
value is 1
value is 2
value is 3
value is 4
value is 5
first print_list---------------
value is 3
value is 1
value is 2
value is 3
value is 4
second print_list--------------
value is 3
value is 1
value is 2
value is 3
value is 4
value is 5
third print_list---------------
value is 3
value is 1
value is 3
value is 4
value is 5
four print_list---------------
list contain node and the value of node is 4

 

 

4 总结

很明显第二种方式更换简单好理解，在函数里面如果我们传递指针进去，然后想修改这个指针的话，我们直接给这个指针赋值来改变这个指针是不可以的，因为是停时变量，我们直接可以返回新malloc的指针或者函数传递二级指针作为参数，在函数里面修改这个指针，同时我们把头结点传递函数里面去，我们直接操作head->next = head->next->next;这些都会有效.

用C语言实现的话，我们喜欢搞个头结点，然后每个函数里面传入头结点，我们函数里面改变的是head->next的值，但是我们就算移动了head节点，比如head = head->next; 但是实际上没有影响，因为是零时变量，最后的head的位置还是没有动