单链表基本操作

#include<iostream>#include"stdlib.h"using namespace std;typedef struct node          //定义结点{    int data;             //结点的数据域为整型    struct node *next;      //结点的指针域}ListNode;int dataflag = 0;int reverseflag = 0;typedef ListNode * LinkList;         // 自定义LinkList单链表类型LinkList CreatListR1(LinkList head);              //函数，用尾插入法建立带头结点的单链表ListNode *LocateNode(LinkList head, int key);              //函数，按值查找结点void DeleteList(LinkList head,int key);                   //函数，删除指定值的结点void printlist(LinkList head);                    //函数，打印链表中的所有值void DeleteAll(LinkList *L);                    //函数，删除所有结点，释放内存void DeletePioneer(LinkList head, int x);//删除指定值的前驱结点void DeleteRepeat(LinkList head);//删除重复void DeleteUI();//删除界面LinkList InvertedSequence(LinkList head2);//逆序void ui();//==========主函数==============void main(){  int num, key, x, choose, dechoose, fichoose;  char ch;  LinkList head, t, head2;  t = (LinkList)malloc( sizeof(ListNode));  while(1)  {    system("cls");    ui();    cin>>choose;    if(choose == 1)    {        head = CreatListR1(head);          //用尾插入法建立单链表，返回头指针        printlist(head);             //遍历链表输出其值        printf("\n");        cout<<"按任意键返回"<<endl;        fflush(stdin);        getchar();    }    else if(choose == 2)    {        system("cls");        DeleteUI();        printlist(head);        cin>>dechoose;        if(dechoose == 1)        {            cout<<"请输入删除的值:";            scanf("%d",&key);            DeleteList(head,key);            printlist(head);        }        else if(dechoose == 2)        {            printlist(head);            cout<<"请输入删除的值:";            scanf("%d",&key);            DeletePioneer(head,key);            printlist(head);        }        else if(dechoose == 3)        {            DeleteRepeat(head);            printlist(head);        }        else if(dechoose == 4)        {            DeleteAll(&head);        }        else        {        }        fflush(stdin);        cout<<"按任意键回到主界面"<<endl;        getchar();    }    else if(choose == 3)    {        printlist(head);        if(dataflag == 1)        {        cout<<"请输入查找的值:";        scanf("%d",&key);        LocateNode(head, key);        }        fflush(stdin);        cout<<"按任意键返回"<<endl;        getchar();    }    else if(choose == 4)    {        printlist(head);        fflush(stdin);        cout<<"按任意键返回"<<endl;        getchar();    }    else if(choose == 5)    {        printlist(head);             //遍历链表输出其值        head2 = InvertedSequence(head);        reverseflag = 1;        printlist(head2);        reverseflag = 0;        fflush(stdin);        cout<<"按任意键返回"<<endl;        getchar();    }    else    {        return;    }  }}void ui(){    printf("    欢迎进入单链表操作界面\n");    printf("  1.插入数据\n");    printf("  2.删除数据\n");    printf("  3.查找数据\n");    printf("  4.显示数据\n");    printf("  5.逆序显示数据\n");    printf("  6.退出程序\n");}void DeleteUI(){    printf("    删除界面\n");    printf("  1.删除当前节点数据\n");    printf("  2.删除前驱节点数据\n");    printf("  3.删除重复节点数据\n");    printf("  4.删除所有节点数据\n");    printf("  5.返回主界面\n");}LinkList CreatListR1(LinkList head)//尾插法 {    int n, i;    int x;    LinkList p, q;    head = (LinkList)malloc( sizeof(ListNode));    head->next = NULL;    cout<<"请输入结点数量:";    cin>>n;    cout<<"请输入结点值:";    for(i = 0; i < n; i++)    {        //非递减有序单链表输入        while(1)        {            scanf("%d",&x);            if(i == 0 ||x >= q->data)                break;            else            {                printf("输入错误,请重新输入\n");            }        }        //scanf("%d",&x);        p = (LinkList)malloc( sizeof(ListNode));        p->data = x;        p->next = NULL;        if(head->next == NULL)            head->next = p;        else             q->next = p;        q = p;    }    q->next = NULL;    dataflag = 1;//表示有数据    return head;        //返回头指针}ListNode *LocateNode(LinkList head, int key)//按值查找{    LinkList p;    p = head->next;    while( p != NULL&& p->data != key)    {        p = p->next;    }    if(p != NULL)    {        cout<<"找到了";        cout<<p->data<<endl;        return p;    }    else    {        cout<<"没找到\n";        return NULL;    }}void DeleteList(LinkList head,int key)//删除值为key的节点{    //按key值查找结点的    //若没有找到结点，退出    //若找到，则从单链表中删除该结点，并释放结点    LinkList p, q, t;    p = head->next;    q = head->next;    while(   p != NULL&& p->data != key )    {    //  cout<<"p"<<endl;        p = p->next;        q = p;    }    if(q == head->next) //q是第一个节点    {        head->next = q->next;        free(q);        return;    }    //q是p的前一个节点    t = head->next;    while(t->next != q)    {        t = t->next;    }    //t是q的前一个节点    if(p != NULL)//找到了删除q这个结点    {    //  cout<<"t"<<endl;        t->next = q->next;      }    else//没找到    {        cout<<"数据中没有这个值,删除失败"<<endl;        return;    }    free(q);}void DeletePioneer(LinkList head, int x)//删除指定结点的前驱结点{    LinkList p, q, t;    p = head->next;    while(p && p->data != x)    {        q = p;        p = p->next;        }//q是p的前驱结点目的删除q    t = head->next;    while(t->next != q)    {        t = t->next;    }//t是q的前驱结点    if(p != NULL)    {        t->next = p;        free(q);    }    else    {        printf("链表中无其值\n");    }}void DeleteAll(LinkList *L)//删除所有结点{    LinkList p, q;    p = (*L)->next;    while(p)    {        q = p->next;        free(p);        p = q;    }    (*L)->next = NULL;    dataflag = 0;    printf("所有结点已删除\n");} void printlist(LinkList head)//打出结点{    LinkList t;    t = head->next;    if(t == NULL)    {        printf("无数据\n");        return;    }    if(reverseflag != 1)    cout<<"\n当前所有数据为:";    else if(reverseflag == 1)        cout<<"\n逆序显示所有数据：";    while(t != NULL)    {        cout<<t->data<<' ';        t = t->next;    }    printf("\n");}void DeleteRepeat(LinkList head){    LinkList t, k, q;    for(t = head->next;t->next != NULL && t != NULL;)    {        if(t->data == t->next->data)//前一个等于后一个        {            q = t->next;            t->next = q->next;            free(q);        }        else        {        t = t->next;        }    }}//单链表逆序 取出来数据 用头插法插给另一个链表LinkList InvertedSequence(LinkList head2){    LinkList t, p;    int x;    t = head2->next;    head2 = (LinkList)malloc( sizeof(ListNode));    head2->next = NULL;    while(t != NULL)    {        x = t->data;        p = (LinkList)malloc( sizeof(ListNode));        p->data = x;        p->next = head2->next;        head2->next = p;        t = t->next;    }    return head2;}