c语言实现链表的创建、增、删、改、查

////  main.c//  链表的基本操作//  Created by fzl //  Copyright ©  fzl All rights reserved.//#include <stdio.h>#include <stdlib.h>#define FILENAME "/Users/fzl/Desktop/2.txt"struct Student{    int num;    char name[20];};typedef enum Same{    isSame,    isDifferent}Same;typedef struct Student Student;struct LINK{    Student data;    struct LINK *next;};typedef struct LINK LINK;typedef LINK * pLINK;Same SameOrNot(pLINK head,Student stu){    pLINK temp=head->next;    for (; temp!=NULL; temp=temp->next)    {        if(temp->data.num==stu.num)        {            return isSame;        }    }    if(temp==NULL)    {        return isDifferent;    }    return isSame;}/** 创建链表 */pLINK createList(pLINK head){    if(NULL==head)    {        //定义头结点        head=(pLINK)malloc(sizeof(LINK));        head->next=NULL;    }    printf("创建链表成功\n");    return head;}/**打印链表 */void printList(pLINK head){    if(head==NULL)    {        printf("没有创建链表\n");        return;    }    if(head->next==NULL)    {        printf("无信息打印\n");        return;    }    pLINK temp=head->next;    for (; temp!=NULL; temp=temp->next)    {        printf("[%d %s]--->",temp->data.num,temp->data.name);    }    printf("NULL\n");}Student getData(pLINK head){    Student stu;    while (1)    {        printf("请输入插入学生的信息[学号 姓名]:");        scanf("%d%s",&stu.num,stu.name);        if(SameOrNot(head, stu)==isSame)        {            printf("输入重复\n");        }        else        {            return stu;        }    }    return stu;}/**头插 */void headInsert(pLINK head){    //新建节点    pLINK p=(pLINK)malloc(sizeof(LINK));    //填补数据域    p->data=getData(head);    //将新建的节点连到链表中    p->next=head->next;    head->next=p;    printf("头插成功\n");}void tailInsert(pLINK head){    pLINK p=(pLINK)malloc(sizeof(LINK));    p->data=getData(head);    if(head->next==NULL)    {        head->next=p;        p->next=NULL;        return ;    }    pLINK tail=head->next;    for (;tail->next!=NULL; tail=tail->next)    {    }   //如果循环能跳出，则tail->next==NULL，说明tail就是尾指针    tail->next=p;    p->next=NULL;    printf("尾插成功\n");}int getListLength(pLINK head){    pLINK temp=head->next;    int length=0;    for (; temp!=NULL; temp=temp->next)    {        length++;    }    return length;}void randomInsert(pLINK head){    int index=0;    printf("请输入要插入的位置:");    scanf("%d",&index);    if(index<=0||index>getListLength(head)+1)    {        printf("你输入的位置有误\n");    }    if(index==1)    {        headInsert(head);    }    else if (index==getListLength(head)+1)    {        tailInsert(head);    }    else    {        pLINK front;        int i;        for (front=head->next,i=1; i<index-1; front=front->next,i++)        {        }        pLINK p=(pLINK)malloc(sizeof(LINK));        p->data=getData(head);        p->next=front->next;        front->next=p;    }    printf("任意插入数据成功\n");}pLINK insertData(pLINK head){    if(head==NULL)    {        head=createList(head);    }    int select;    while (1)    {        printf("=========\n");        printf("1.头插\n");        printf("2.尾插\n");        printf("3.任意位置插入\n");        printf("4.返回上一层\n");        printf("=========\n");        scanf("%d",&select);        switch (select)        {            case 1:                headInsert(head);                break;            case 2:                tailInsert(head);                break;            case 3:                randomInsert(head);                break;            case 4:                return head;            default:                break;        }    }    return head;}void tailDelete(pLINK head){    if(head==NULL||head->next==NULL)    {        printf("无数据可删\n");        return;    }    pLINK front=head;    for (; front->next->next!=NULL; front=front->next)    {    }    //front->next->next==NULL    pLINK tail=front->next;    front->next=NULL;    free(tail);    printf("尾删成功\n");}void headDelete(pLINK head){    if(head==NULL||head->next==NULL)    {        printf("无数据可删\n");        return;    }    pLINK current=head->next;    head->next=current->next;    free(current);    printf("删除成功\n");}void randomDelete(pLINK head){    if(head==NULL||head->next==NULL)    {        printf("无数据可删\n");        return;    }    printf("请输入要删除的位置:");    int index=0;    scanf("%d",&index);    if(index<=0||index>getListLength(head))    {        printf("输入位置有误\n");        return;    }    if(index==1)    {        headDelete(head);    }    else if (index==getListLength(head))    {        tailDelete(head);    }    else    {        pLINK front;        int i;        for (front=head->next,i=1; i<index-1; front=front->next,i++)        {        }        pLINK current=front->next;        front->next=current->next;        free(current);    }    printf("任意删除数据成功\n");}void deleteData(pLINK head){    if(head==NULL||head->next==NULL)    {        printf("无数据可删\n");        return;    }    int select;    while (1)    {        printf("=========\n");        printf("1.头删\n");        printf("2.尾删\n");        printf("3.任意位置删除\n");        printf("4.返回上一层\n");        printf("=========\n");        scanf("%d",&select);        switch (select)        {            case 1:                headDelete(head);                break;            case 2:                tailDelete(head);                break;            case 3:                randomDelete(head);                break;            case 4:                return;            default:                break;        }    }}void searchData(pLINK head){    if(head==NULL||head->next==NULL)    {        printf("无数据查询\n");        return;    }    printf("请输入要查询的学生的学号:");    int num;    scanf("%d",&num);    pLINK temp=head->next;    for (; temp!=NULL; temp=temp->next)    {        if(temp->data.num==num)        {            printf("这个学生的信息[%d %s]\n",temp->data.num,temp->data.name);            return;        }    }    if(temp==NULL)    {        printf("查无此人\n");        return;    }}void changeData(pLINK head){    if(head==NULL||head->next==NULL)    {        printf("无数据查询\n");        return;    }    printf("请输入要修改的学生的学号:");    int num;    scanf("%d",&num);    pLINK temp=head->next;    for (; temp!=NULL; temp=temp->next)    {        if(temp->data.num==num)        {            printf("这个学生原信息为[%d %s]\n",temp->data.num,temp->data.name);            printf("请输入要修改的信息[学号 姓名]:");            scanf("%d%s",&temp->data.num,temp->data.name);            return;        }    }    if(temp==NULL)    {        printf("查无此人\n");        return;    }}pLINK readFileToMemory(){    pLINK head=(pLINK)malloc(sizeof(LINK));    pLINK p=head;    //1.打开文件    FILE *fp=fopen(FILENAME, "r");    if(fp==NULL)    {        perror("fopen failed");        return NULL;    }    //2.    int length=0;    fread(&length, sizeof(int), 1, fp);    int i=1;    for (; i<=length; i++)    {        pLINK q=(pLINK)malloc(sizeof(LINK));        fread(&q->data, sizeof(Student), 1, fp);        p->next=q;        q->next=NULL;        p=p->next;    }    //3    fclose(fp);    return head;}void saveDataToFile(pLINK head){    if(head==NULL||head->next==NULL)    {        printf("无数据可保存\n");        return;    }    //1.打开文件    FILE *fp=fopen(FILENAME, "w");    if(fp==NULL)    {        perror("fopen failed");        return;    }    int length=getListLength(head);    fwrite(&length, sizeof(int), 1, fp);    //2.对文件进行写    pLINK temp=head->next;    for (; temp!=NULL; temp=temp->next)    {        fwrite(&temp->data, sizeof(Student), 1, fp);    }    //3.关闭文件    fclose(fp);}int main(){    pLINK head=NULL;    int select;    while (1)    {        printf("=========\n");        printf("1.创建链表\n");        printf("2.插入数据\n");        printf("3.删除数据\n");        printf("4.打印链表\n");        printf("5.查询数据\n");        printf("6.修改数据\n");        printf("7.保存数据到文件\n");        printf("8.读取文件\n");        printf("0退出\n");        printf("=========\n");        scanf("%d",&select);        switch (select)        {            case 1:                head=createList(head);                break;            case 2:                head=insertData(head);                break;            case 3:                deleteData(head);                break;            case 4:                printList(head);                break;            case 5:                searchData(head);                break;            case 6:                changeData(head);                break;            case 7:                saveDataToFile(head);                break;            case 8:                head=readFileToMemory();                break;            case 0:                return 0;            default:                break;        }    }    return 0;}