#include <stdio.h>
#include <stdlib.h>
#include <string.h>//定义类型
typedef struct Stlianbiao
{char name[20];struct Stlianbiao *next;
}SLB;void createLB(SLB **head)
{//定义辅助指针SLB *p = NULL;SLB *cur = NULL;SLB *c = NULL;//定义接受字符串变量char name[20];//判断指针是否合法if (head == NULL){printf("createLB ERROR..");return;}//分配头指针内存p = (SLB *)malloc(sizeof(SLB));memcpy(p->name, "head", 20);p->next = NULL;//赋值当前指针cur = p;printf("ENTER A NAME TO CREATE A BL,0 TO EXIT:");//输出姓名scanf("%s", name);//当输入字符串为0时候停止循环while (strcmp(name,"0") != 0){//分配内存c = (SLB *)malloc(sizeof(SLB));memcpy(c->name, name, sizeof(name));c->next = NULL;//连接cur->next = c;//移动当前指针cur = c;//下一项printf("ENTER A NAME TO CREATE A BL,0 TO EXIT:");//输出姓名scanf("%s", name);}//指针作输出*head = p;
}//删除指定项
void delLB(SLB *head,char *name)
{//定义辅助指针SLB * cur = NULL, *pre = NULL;//判断指针是否合法if (head == NULL){printf("delLB ERROR..");return;}pre = head;cur = head->next;while (cur){//如果找到指定项则删除并中断循环if (!strcmp(cur->name,name)){pre->next = cur->next;free(cur);break;}//移动辅助指针pre = cur;cur = pre->next;}
}//在指定项面前插入项 如果没有指定项则在最后插入项
void insertLB(SLB *head, char *name,char *in)
{//定义辅助指针SLB * cur = NULL, *pre = NULL,*c =NULL;//判断指针是否合法if (head == NULL){printf("insertLB ERROR..");return;}pre = head;cur = head->next;while (cur){//当前项是要找的项则退出遍历if (!strcmp(cur->name, name)){break;}//移动指针pre = cur;cur = pre->next;}//分配内存c = (SLB *)malloc(sizeof(SLB));memset(c->name, 0, 20);memcpy(c->name, in, 20);//插入操作c->next = cur;pre->next = c;
}//遍历打印链表
void printLB(SLB *head)
{//判断指针是否合法if (head == NULL){printf("printLB ERROR..");return;}//开始打印printf("START ");head = head->next;while (head){printf("%s ", head->name);//移动指针head = head->next;}//结束打印printf(" END\n");
}//释放内存
void freeLB(SLB **head)
{//当前指针SLB * cur = NULL;//判断指针是否合法if ((*head) == NULL){printf("freeLB ERROR..");return;}//释放后面的项cur = (*head)->next;while (cur){//断开当前指针 连接应当相邻指针(*head)->next = cur->next;//释放当前指针free(cur);//移动当前指针cur = (*head)->next;}//释放头指针free(*head);//避免野指针*head = NULL;
}//链表逆置
void reverseLB(SLB *head)
{//定义辅助指针 temp缓存指针SLB * temp = NULL, *p = NULL, *q = NULL;//头指针为空错误if (head == NULL){printf("reverseLB ERROR..");return;}//只有一项一下则不需要逆置if (head->next == NULL || head->next->next == NULL){printf("reverseLB is the same..");return;}//p q分别为第一 第二项p = head->next;q = p->next;while (q != NULL){//缓存下一项temp = q->next;//逆置q->next = p;//移动指针p = q;q = temp;}//处理剩余的head->next->next = NULL;head->next = p;
}void main()
{//定义一个头指针SLB *head = NULL;//指针作输出 创建头指针并创建链表createLB(&head);printLB(head);//链表逆置
    reverseLB(head);printLB(head);//删除 删除链表中名字为20的项delLB(head, "20");printLB(head);//插入 在30之前插入300 如果不存在30则在最后插入300insertLB(head, "30", "300");printLB(head);//插入 在200之前插入20000 如果不存在30则在最后插入300insertLB(head, "200", "20000");printLB(head);//释放内存 用二级指针 避免野指针freeLB(&head);system("pause");
}