单向循环链表的操作

#include <stdio.h>

 

struct node

{

    int num;

 

    struct node *next;

};

typedef struct node Node;

typedef Node * Link;

 

void creat_link(Link *head)

{

    //*head = NULL;

    *head = (Link)malloc(sizeof(Node));

    (*head)->next = *head;

}

 

void insert_head_node(Link *newnode, Link *head)

{

    (*newnode)->next = (*head)->next;

    (*head)->next = *newnode;

}

 

void insert_tail_node(Link *newnode, Link *head)

{

        Link temp = *head;

 

while(temp->next != *head)

{

            temp = temp->next;

}

 

temp->next = *newnode;

(*newnode)->next = *head;

}

 

int insert_mid_node(Link *newnode, Link *head, int num)

{

 

    Link temp = (*head)->next;

 

    while(temp != *head)

    {

        if(temp->num == num)

{

            (*newnode)->next = temp->next;

    temp->next = *newnode;

    return 0;

}

temp = temp->next;

    }

}

 

int delete_node(int num, Link *head)

{

 

    Link ptr = *head;

 

    Link temp = ptr->next;

    while(temp != *head)

    {

        if(temp->num == num)

{

    ptr->next = temp->next;

    free(temp);

    temp = NULL;

    return 0;

}

ptr = temp;

temp = temp->next;

    }

}

 

int reverse_link(Link *head)

{

    if((*head)->next == *head || (*head)->next->next == *head)

    {

        return 0;

    }

 

    Link ptr = *head;

    Link str = ptr->next;

    Link temp = str->next;

 

    while(temp != *head)

    {

        str->next = ptr;

 

ptr = str;

str = temp;

temp = temp->next;

    }

 

    str->next = ptr;

 

 

    (*head)->next = str;

}

 

int display_link(Link *head)

{

 

    Link temp = (*head)->next;

 

    while(temp != *head)

    {

        printf("%d\n",temp->num);

temp = temp->next;

    }

}

 

int main()

{

    int i;

    

    Link head;

    Link newnode;

 

    creat_link(&head);

    

    for(i = 0; i < 10; i++)

    {

        newnode = (Link)malloc(sizeof(Node));

newnode->num = i + 1;

insert_head_node(&newnode,&head);

//insert_tail_node(&newnode,&head);

//insert_mid_node(&newnode,&head);

    }

 

    display_link(&head);

#if 1

    newnode = (Link)malloc(sizeof(Node));

 

    newnode->num = 5;

 

    insert_mid_node(&newnode,&head,8);

    

    display_link(&head);

 

    delete_node(7,&head);

    reverse_link(&head);

 

    display_link(&head);

   #endif

    return 0;

}