c语言单项链表学习随笔

//

//  main.c

//  C语言单项链表

//

//  Created by Pakho on 2017/5/16.

//  Copyright ? 2017年 Pakho. All rights reserved.

//

#include <stdio.h>

#include <stdlib.h> // malloc 可以开辟指定大小的内存空间

#include <string.h>

// 是否需要补齐，要看开辟的总空间是不是最大成员变量所占内存的倍数

// 定义一个节点（node）的结构体

struct Student {

    char name[20];        // 储存学生姓名

    int age;              // 储存学生年龄

    struct Student * next;// 指向下一个节点

};

// 创建一个新节点并返回其地址

struct Student * newNode(){

    // 开辟一个大小为 32 的地址空间，并强制转化为（struct Student *）的指针

    struct Student * stu = (struct Student *)malloc(sizeof(struct Student));

    printf("请输入姓名： \n");

    // scanf("%s",&stu->name[0]);

    scanf("%s",stu->name); // 给姓名赋值

    

    printf("请输入年龄： \n");

    // 参数表示后面对应的接受值类型，因为 age 是int 类型，所以要用 %d

    scanf("%d",&stu->age); // 给年龄赋值

    // stu-age 是等价于 (*stu).age

    //printList("%p",&stu->age);

    //printList("%p",&(*stu).age);

    stu->next = NULL;      // 默认尾指针 = NULL
    return stu;

}
struct Student * creatList(){

    struct Student * head = newNode();

    struct Student * preNode = head; // 最开始的前指针为头指针

    struct Student * node = newNode();

    // 当新建的节点 age != 0 的时候，就串联到链表上去

    while (node->age!=0) {

        preNode->next = node; // 1.让前节点指向新节点

        preNode = node;       // 2.让最后一个节点成为心的节点

        node = newNode();     // 3.继续创建新节点

    }

    return head;

}

void printList(struct Student * head){

    printf("====================\n");

    //struct Student * temp = head;

    if(head != NULL){

        printf("姓名：%s\n",head->name);

        printf("年龄：%d\n",head->age);

        printf("下一个节点地址：%p\n",head->next);

        printList(head->next);

        //temp = temp->next;

    }
}

/*

 查询

 head 要查询的链表

 node 是要查询的节点（只查询是否包含相同信息）

 */

int indexOfNode(struct Student * head,struct Student * node){

    int index = 0;

    // 创建一个中间变量，避免 head 指针随着 next 改变

    struct Student * temp = head;

    while (temp != NULL) {

        if(strcmp(temp->name,node->name) == 0 && temp->age == node->age){

            return index;

        }

        index++;

        temp = temp->next;

    }

    return  -1;

}
// 删除

void deleteNode(struct Student ** head,struct Student * node){

    struct Student * temp = *head;

    struct Student * prehead = *head ;

    while (temp != NULL) {

        if(strcmp(temp->name,node->name) == 0 && temp->age == node->age){

            

            if (prehead == temp) {

                *head = temp->next;

                break;

            }

            prehead->next = temp->next;

            break;

        }

        prehead = temp;

        temp = temp->next;
    }

}

// 删除2（没有二级指针）

struct Student * deleteNode2(struct Student * head,struct Student * node){

    struct Student * temp = head;

    struct Student * prehead = head ;

    while (temp != NULL) {

        if(strcmp(temp->name,node->name) == 0 && temp->age == node->age){

            if (prehead == temp) {

                head = temp->next;

                return head;

            }

            prehead->next = temp->next;

            return head;

        }

        prehead = temp;

        temp = temp->next;
    }

    return head;
}

int changdu(struct Student * head){

    int index = 0;

    struct Student * temp = head;

    while (temp->next!= NULL) {

        temp = temp->next;

        index++;

    }

    index++;

    return  index;

}

//插入

struct Student * insert(struct Student * head,struct Student * node,int a){

    struct Student * temp = head;

    struct Student * temp1 = head;

    while (head != NULL) {

        if (a<=1) {

            node->next=head;

            head = node;

            return head;

        }

        else if (a>changdu(head)){

            while (temp->next!=NULL) {

                temp = temp->next;

            }

            temp->next = node;

            node->next = NULL;

            return head;

        }else{

            int i;

            for (i=0; i<a; i++) {

                temp1=temp;

                temp = temp->next;

            }

            temp1->next = node;

            node->next = temp;

            return head;
        }
    }
    return head;
}

struct Student * insertNodeAtIndex(struct Student * head,struct Student * node,int index){

    struct Student * temp = head;

    struct Student * preNode = head;

    int i =1;

    while (temp != NULL) {

        if (index == 1) {

            node->next = head;

            return head;

        }else if (index == i){

            preNode->next = node;

            node->next = temp;

            return head;

        }

        preNode = temp;

        temp = temp->next;

        i++;

    }

    preNode->next=node;

    return head;

}

int main(int argc, const char * argv[]) {

    struct Student * stu =  creatList();

    int a = changdu(stu);

    printList(stu);

    printf("链表长度是%d\n",a);

    while (1) {

        //printf("请输入你要查询的节点信息:\n");

        printf("请输入你要删除的节点信息:\n");

        struct Student * node = newNode();

        //int b = 0;

        //scanf("请输入你要插入的位置%d",&b);

        //printf("%d",b);

        deleteNode(&stu, node);

        //printList(stu);

        //printList(insert(stu, node, 2));

        //int ret = indexOfNode(stu,node);

        //if(ret == -1){

        //  printf("没有你要查找的节点\n");

        //}else{

        //   printf("你查找的节点在 %d 位置\n",ret);

        // }

    }

    return 0;

}