链表——单链表的实现

用单链表来记录用户输入的数值， 个数不确定。直到输入的数为-1为止

 

include <stdio.h>
#include <stdlib.h>

struct mylist {
    int data;

    struct mylist *next;
};

//用链表来记录用户输入的数值， 个数不确定。直到输入的数为-1为止

int main(void)
{
    int num;
    struct mylist *head = NULL,  //用于存放链表的头节点地址
              *new = NULL;   //用于存放新产生的节点地址

    while (1)
    {
        printf("input num:");
        scanf("%d", &num);

        if (num < 0)
            break;
        //产生一个链表的新节点，用于存放刚输入的值
        new = malloc(sizeof(*new));
        new->data = num;
        new->next = NULL;

        //加入链表去    
        if (NULL == head)
            head = new; //当没有头节点时，新节点则成为头节点
        else
        {
            new->next = head; //新的节点指向头节点        
            head = new;       //新节点作头节点
        }    
    }

    for (new = head; new != NULL; new = new->next)
    {
        printf("%d\n", new->data);
    }

    return 0;
}

现在要把1，2，3存到链表里。有两个节点，都指向NULL，head1的data为1（head == NULL），head1成了头节点，head1->next 还是为NULL。第二步， head2 的data 为2(head == new)，头不为NULL，运行else，head2->next = head1. head1 =head2.

第三步，在第二步里 head1 = =head2 , head3->next = head2, head1 == head3.

/////////////////////记录字符串/////////////////////////////

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct mylist_t {
    char name[64];
    struct mylist_t *next;
};

int main(void)
{
    struct mylist_t *head = NULL, *new = NULL;
    while(1)
    {
        new = malloc(sizeof(new));
        printf("name:");
        scanf("%s",new->name);
        if(strcmp("exit" ,new->name) == 0)
                {
                    free(new);
                    break;
                }
        new->next = NULL;
        if(head == NULL)
            head = new;
        else
        {    
            new->next = head;
            head = new;
            
        }

    }
     struct mylist_t *tmp;
    for(new = head; new != NULL;)
    {
        printf("name = %s \n",new->name);
        tmp = new->next;
        free(new);
        new =tmp;
    
    }

    return 0;

}

 

 ////////////////////指针记录字符串//////////////////////

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct mylist{
    char *line;
    struct mylist *next;
};

int main(void)
{
    struct mylist *head = NULL, *new = NULL;

    while(1)
    {
        new= malloc(sizeof(new));
        new->line = malloc(sizeof(1024));
        printf("input string:");
        scanf("%s", new->line);
        if(strcmp("null",new->line) == 0)
        {
                free(new->line);
                free(new);

                break;
        }
        new->next = NULL;

        if(head == NULL)
                head = new;
        else
        {
            new->next = head;
            head = new;
        }

    }
    struct mylist *tmp ;
    for (new = head; new != NULL; )
            {
                        printf("%s\n", new->line);
                            tmp =new->next;
                            free(new->line);
                            free(new);
                            new = tmp;
            }

                return 0;
}

前面都是没头节点的单链表，下面是有头节点的单链表

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct mylist_t {
    int data;
    struct mylist_t *next;
};

int main(void)
{
    struct mylist_t head = {0, NULL}, *new;
    int num;
    while(1)
    {
        printf("input num:");
        scanf("%d",&num);
        if(num < 0)
                break;
        new = malloc(sizeof(new));
        new->data = num;
        new->next = head.next;
        head.next = new;
    }
    struct mylist_t *tmp;
    for(new = head.next; new != NULL;)
    {
        printf("%d\n",new->data);
        tmp = new->next;
        free(new);
        new = tmp;
    }
    return 0;
}

 先进先出的链表

#include <stdio.h>
#include <stdlib.h>
#include <string.h>


struct mylist {
    int data;
    struct mylist *next;
};

int main(void)
{
    int num;
    struct mylist *new ,*tail = NULL, head = {0,NULL};
    while(1)
    {
        printf("input num:");
        scanf("%d",&num);
        if(num < 0)
                break;
        new = malloc(sizeof(new));
        new->data = num;
        new->next = NULL;

        if(NULL == head.next)
            head.next = new;
        else
            tail->next = new;
        tail = new;
    }

    struct mylist *tmp;
    for(new = head.next; new != NULL ; tmp = new->next,free(new), new = tmp)
            printf("num:%d\n",new->data);

    return 0;
}

单链表的删除

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct mylist {
    int data;
    struct mylist *next;
};


int add(struct mylist *head)
{
    int num;
    struct mylist *new;
    printf("input data:");
    scanf("%d",&num);
    if(num < 0)
        return -1;
    new = malloc(sizeof(new));
    new->data  = num;
    new->next = head->next;
    head->next = new;

    return 0;

}
void show(struct mylist *head)
{
    struct mylist *new;
    for(new= head->next; new != NULL; new = new->next)
        printf("data:%d\n", new->data);
}

struct mylist * find_del(struct mylist *head,int num)
{
    struct mylist *n,*tmp;
    for(n = head->next; n != NULL;)
    {

        if(num == n->data)
        {
            printf("%d\n",n->data);
            tmp->next = n->next;
            free(n);
            return n;
        }
        tmp = n;
        n=n->next;
    }
        return 0;
}

int main(void)
{
    struct mylist head = {0, NULL}, *new;
    while(add(&head) == 0)
        ;
    show(&head);
    new = find_del(&head, 3);
    show(&head);
        return 0;

}

 链表的倒置

include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct mylist {
    int data;
    struct mylist *next;

};

int main(void)
{
    int num;
    struct mylist *new, head= {.next = NULL};

    while(1)
    {
        printf("input data:");
        scanf("%d",&num);
        if(num < 0)
            break;
        new = malloc(sizeof(new));
        new->data = num;
        new->next= head.next;
        head.next = new;
        
    }
    for(new= head.next; new != NULL; new= new->next)
        printf("num:%d\n",new->data);

    ////////////////链表的倒置/////////////////////

    struct mylist *tmp , head2 = {0, NULL};
    for(new = head.next; new != NULL;)
    {
            tmp = new->next;//先把new->next存起来，要改new;
        new->next = head2.next;
        head2.next = new;
        new = tmp;
    }
    for(new= head2.next; new != NULL; new= new->next)
        printf("num:%d\n",new->data);
    return 0;
}