C的链表实现

#include<stdio.h>#include<stdlib.h>struct node{    int num;    struct node *next;};struct node *head=NULL;cre_list() //初始化结点{    head = (struct node *)malloc(sizeof(struct node));    head->next = NULL;}add_node(int num) //插入结点{    struct node *ptr = (struct node *)malloc(sizeof(struct node));    ptr->num = num;    ptr->next = head;    head=ptr;}add_five_node(int num) //在5之后插入结点{    int i = 0;    struct node *p,*q;    p=head;    q=head;    struct node *ptr = (struct node *)malloc(sizeof(struct node));    ptr->num = num;    while((p->num)!=5)    {        p = p->next;    }    ptr->next=p->next;    p->next=ptr;}struct node *opp_node(struct node *head)//链表逆序{    struct node *p,*front,*q;    front=NULL;    p=head;    while(p!=NULL)    {        q=p->next;//尾插入法        p->next=front;        front=p;        p=q;    }    head =front;    return head;}display_node() //遍历链表{    struct node *p = head;    do    {        printf("%d\t",p->num);        p = p->next;    }while(p != NULL);    printf("\n");}delete_node()  //删除偶数结点{    struct node *p,*q;      p = head;    q = head->next;    while(q != NULL)    {        if((q->num)%2 == 0){       p->next=q->next;    free(q);    q=p->next;    continue;}p = p->next;q = q->next;    }    if((head->num)%2 == 0)    {        p = head;head = head->next;free(p);p = NULL;    }}int main(){    int i=0;    cre_list();    for(i;i<10;i++)    {        add_node(i);    }    display_node();    add_five_node(12);    add_five_node(14);    add_five_node(16);    add_five_node(18);    display_node();    delete_node();    display_node();head=opp_node(head);    display_node();    return 0;}

链表删除偶结点时，head结点暂不考虑，利用两个指针删除从第二个结点开始的偶结点，待删除完之后，再回头判断头结点是否为偶数，若为偶数则删除头结点。