链表增删查

#include <stdio.h>#include <stdlib.h>typedef struct node{ int nDate; struct node *pstnext;}Node;//链表输出void output(Node *head){ Node *p = head->pstnext; while(NULL != p) {  printf("%d  ", p->nDate);   p = p->pstnext; } printf("\r\n");}//链表建立Node* creat(){ Node *head = NULL, *p = NULL, *s = NULL; int Date = 0, cycle = 1; head = (Node*)malloc(sizeof(Node)); if(NULL == head) {  printf("分配内存失败\r\n");  return NULL; } head->pstnext = NULL;  p = head; while(cycle) {  printf("请输入数据且当输入数据为0时结束输入\r\n");  scanf("%d", &Date);  if(0 != Date)  {   s = (Node*)malloc(sizeof(Node));   if(NULL == s)   {    printf("分配内存失败\r\n");    return NULL;   }   s->nDate = Date;   p->pstnext = s;   p = s;  }  else  {   cycle = 0;  } } p->pstnext = NULL; return(head);}//链表按值查找void research_Date(Node *head, int date){ Node *p; int n=1; p = head->pstnext; while(NULL != p && date != p->nDate) {  p = p->pstnext;  ++n; } if(NULL == p) {  printf("链表中没有找到该值"); }else if(date == p->nDate) {  printf("要查找的值%d在链表中第%d个位置\r\n", date, n); } return;}//按序号查找void research_Number(Node *head, int Num){ Node *p=head; int i = 0; while(NULL != p && i < Num) {  p = p->pstnext;  i++; } if(p == NULL) {  printf("查找位置不合法\r\n"); }else if(i == 0) {  printf("查找位置为头结点\r\n"); }else if(i == Num) {  printf("第%d个位置数据为%d\r\n", i, p->nDate); }}//在指定元素之前插入新结点void insert_1(Node *head, int i, int Newdate){ Node *pre = head, *New = NULL; int j = 0; while(NULL != pre && j < i-1) {   pre = pre->pstnext;  j++; } if(NULL == pre || j > i-1) {  printf("插入位置不存在\r\n"); }else {  New = (Node*)malloc(sizeof(Node));  if(NULL == New)  {   printf("分配内存失败\r\n");   return;  }  New->nDate = Newdate;  New->pstnext = pre->pstnext;  pre->pstnext = New; } }//在指定元素之后插入新结点void insert_2(Node *head, int i, int Newdate){ Node *pre = head, *New = NULL; int j = 0; while(NULL != pre->pstnext && j < i) {  pre = pre->pstnext;  j++; } if(j == i) {  New = (Node*)malloc(sizeof(Node));  if(NULL == New)  {   printf("分配内存失败\r\n");   return;  }  New->nDate = Newdate;  New->pstnext = pre->pstnext;  pre->pstnext = New; }else {  printf("插入位置不存在\r\n"); }}//删除指定结点void Delete_1(Node *head, int i3){ Node *p = head, *pre = NULL; int j = 0; while(NULL != p && j < i3) {  pre = p;  p = p->pstnext;  j++; } if(NULL == p) {  printf("删除位置不存在\r\n"); }else {  pre->pstnext = p->pstnext;  free(p); }}int main(){ int date, num;    //待查找数据 int i3;     //指定删除元素的位置 int i1, i2, Newdate_1, Newdate_2;    //待插入的新数据 Node *Head = NULL;   //定义头结点 Node *Head_New = NULL; //链表建立 Head = creat(); printf("输出建立的单链表\r\n"); output(Head); //链表按值查找 printf("请输入待查找的数据\r\n"); scanf("%d", &date);    research_Date(Head, date); //链表按序号查找 printf("请输入待查找序号\r\n"); scanf("%d", &num); research_Number(Head, num); //在指定第i1个元素之前插入新元素Newdate printf("在指定第i个元素之前插入新元素Newdate"); printf("请输入i与元素且以逗号间隔\r\n"); scanf("%d,%d", &i1, &Newdate_1); insert_1(Head, i1, Newdate_1); printf("插入后新链表\r\n"); output(Head);  //在指定第i2个元素之后插入新元素Newdate printf("在指定第i个元素之后插入新元素Newdate"); printf("请输入i与元素且以逗号间隔\r\n"); scanf("%d,%d", &i2, &Newdate_2); insert_2(Head, i2, Newdate_2); printf("插入后新链表\r\n"); output(Head);  //指定删除i3元素 printf("删除元素的位置\r\n"); scanf("%d", &i3); Delete_1(Head, i3); printf("删除后新链表\r\n"); output(Head); return 0;}