【C】单向链表和双向链表的插入

typedef  struct NODE {    struct NODE *link;    int         value;} Node;typedef struct DNODE {    struct DNODE *fwd;    struct DNODE *bwd;    int value;} Dnode;# s11_node.h ################include <stdio.h>#include <stdlib.h>#include "s11_node.h"#define FALSE 0#define TRUE 1int d11_insert(register Dnode *proot,int value){    register Dnode *this;    register Dnode *next;    register Dnode *newnode;    /**     * 查查value是否存在链表中，如果是就直接返回     * 否则为值创建一个新节点（“newnode”将指向它）     * this指向新节点之前那个节点     * next指向新节点之后那个节点     */    for(this=proot; (next = this->fwd) != NULL; this = next){        if (next->value == value)            return FALSE;        if(next->value > value)            break;    }    newnode = (Dnode *)malloc(sizeof(Dnode));    if(newnode == NULL)        return FALSE;    newnode->value = value;    /*新节点添加到链表中*/    newnode->fwd = next;    this->fwd = newnode;    if(this != proot)        newnode->bwd = this;    else        newnode->bwd = NULL;    if(next != NULL)        next->bwd = newnode;    else        proot->bwd = newnode;    return TRUE;}/** *  单向链表有序插入 */int s11_insert(register Node **plink, int new_value){    register Node *current;    register Node *new;    /*寻找正确的插入位置*/    while((current = *plink) != NULL && current->value < new_value){        plink = &current->link;    }    /*为新节点分配内存*/    new = (Node *)malloc(sizeof(Node));    if(new == NULL){        return FALSE;    }    new->value = new_value;    /*链表中插入新节点*/    new->link = current;    *plink = new;    return TRUE;}int main(int argc, char **argv){    Node *p1;    p1 = NULL;    int i;    for(i=0;i<20;i+=2)        s11_insert(&p1,i);    s11_insert(&p1, 15);    while(p1!=NULL){        printf("%d\n",p1->value);        p1 = p1->link;    }    return EXIT_SUCCESS;}# main.c ######