单循环链表的创建、插入删除等操作

//.....     SClist.h#ifndef _SCLIST_H_#define _SCLIST_H#include<stdio.h>#include<malloc.h>#include<assert.h>#include<stdlib.h>#define  ElemType inttypedef struct Node{ElemType data;struct Node *next;}Node,*PNode;typedef struct List{PNode  first;PNode  last;    int    size;}List;Node * buynode(ElemType x);void InitSCList(List *list);void show_list(List *list);  void push_back(List *list, ElemType x);void push_front(List *list, ElemType x);void pop_back(List *list);void pop_front(List *list);void insert_val(List *list, ElemType x); Node* find(List *list, ElemType x); void quit_system(List *list,int *x); int length(List *list);void delete_val(List *list, ElemType x);void sort(List *list);void reverse(List *list);void clear(List *list);void destory(List *list); #endif//...............SClist.cpp#include"SCList.h"void InitSCList(List *list){Node *s=(Node*)malloc(sizeof(Node));assert(s!=NULL);list->first=list->last=s;list->last ->next=list->first ;list->size=0;}Node* buynode(ElemType x){Node *s=(Node*)malloc(sizeof(Node));assert(s!=NULL);s->data  =x;s->next=NULL;return s;}void push_back(List *list, ElemType x){Node *s=buynode(x);list->last->next =s;list->last=s;list->last ->next =list->first ;list->size ++;}void push_front(List *list, ElemType x){Node *s=buynode(x);s->next=list->first ->next ;list->first ->next =s;if(list->first ==list->last )//插入的结点是第一个节点{ list->last=s;}list->size++;}void pop_back(List *list){if(list->size ==0)return ;Node *p=list->first ;while(p->next!=list->last ){p=p->next ;}free(list->last);list->last=p;list->last ->next =list->first ;list->size--;}void pop_front(List *list){if(list->size ==0)return ;Node *p=list->first ->next;list->first->next =p->next ;free(p);if(list->size ==1)  //删除的是最后一个结点{list->last=list->first;}list->size--;}void insert_val(List *list, ElemType x){Node *p=list->first ;while(p->next!=list->last && p->next ->data <x){p=p->next ;}if(p->next ==list->last && p->next->data <x){push_back(list,x);}else{        Node *s=buynode(x);s->next=p->next;p->next =s;list->size++;}}Node* find(List *list, ElemType x){if(list->size==0)return NULL;Node *p=list->first->next ;while(p!=list->first&&p->data!=x)p=p->next ;if(p==list->first )  //找了一圈还没找到return NULL;return p;}int length(List *list){return list->size;}void delete_val(List *list, ElemType x){if(list->size==0)return ;Node *p=find(list,x);if(p==NULL){printf("要删除的数据不存在.\n");return ;}if(p==list->last )  //找到的是最后一个节点{pop_back(list);}else{Node *q=p->next;p->data =q->data ; //覆盖p->next =q->next;free(q);list->size --;}}//....排序void sort(List *list){if(list->size==0 || list->size ==1)return ;Node *s=list->first ->next ;//第一个节点Node *q=s->next;  //下一个节点list->last ->next =NULL;  //不循环list->last=s;list->last->next=list->first ; //链表后面断开while(q!=NULL){s=q;q=q->next;Node *p=list->first ;while(p->next !=list->last &&p->next ->data <s->data){p=p->next;}if(p->next==list->last &&p->next->data <s->data){s->next =list->last ->next ;list->last ->next =s;list->last =s;}else{s->next =p->next ;p->next=s;}}}void reverse(List *list){if(list->size ==0||list->size ==1)return;Node *p=list->first ->next ;Node *q=p->next ;list->last->next =NULL;list->last =p;list->last ->next =list->first ;    while(q!=NULL){p=q;q=q->next;p->next =list->first ->next ;list->first ->next =p;}}void clear(List *list){Node *p=list->first ->next ;while(p!=list->first ){list->first ->next=p->next ;free(p);p=list->first ->next ;}list->last =list->first ;list->last ->next =list->first ;list->size=0;}void destory(List *list){clear(list);free(list->first );list->first =list->last =NULL;}void quit_system(List *list,int *x){*x=0;}  void show_list(List *list){ Node *p=list->first ->next ; while(p!=list->first ) //不为头，则链表未结束 { printf("%d-->",p->data); p=p->next; } printf("null.\n");}//......List.cpp#include"SCList.h"int  main(){List mylist;InitSCList(&mylist);ElemType  Item;Node *p=NULL;int select=1;Node* pos;while(select){       printf("*********************************\n");       printf("[0] quit_system [1] show_list   *\n");       printf("[2] push_front  [3] push_back   *\n");       printf("[4] pop_front   [5] pop_back   *\n");       printf("[6] insert_val  [7] delete_val*\n");       printf("[8] find_val    [9] length     *\n");       printf("[10] clear      [11] destory    *\n");       printf("[12] reverse    [13] sort       *\n");       printf("*********************************\n");       printf("please input select:>");  scanf("%d",&select);       switch(select)        {   case 0:               quit_system(&mylist,&select);           case 1:               show_list(&mylist);               break;           case 2:                printf("please input data:");                while(scanf("%d",&Item),Item!=-1)                 {                   push_front(&mylist,Item);                 }                break;           case 3:               printf("please input data:");               while(scanf("%d",&Item),Item!=-1)                 {                   push_back(&mylist,Item);                 }                break;           case 4:              pop_front(&mylist);               break;           case 5:              pop_back(&mylist);              break;           case 6:                printf("please input the insert val:");                scanf("%d",&Item);                insert_val(&mylist,Item);                break;           case 7:               printf("please input the delete data:");               scanf("%d",&Item);               delete_val(&mylist,Item);               break;           case 8:               printf("please input the find data:");               scanf("%d",&Item);               pos=find(&mylist,Item);               if(pos== NULL)  {                     printf("can't find this data.");  }  break;           case 9:                 printf("the list's length is:%d",length(&mylist));printf("\n");                 break;           case 10:               clear(&mylist);               break;           case 11:               destory(&mylist);                break;           case 12:                reverse(&mylist);                break;   case 13:                sort(&mylist);                break;           default:               break;         }         system("pause");          system("cls ");    }      return 0;}