新手求助~一个关于链表的问题。。。

《新手求助~一个关于链表的问题。。。》有 0 条评论

1. lxrmido 说：

   2009 年 12 月 29 日下午 4:41

   这个源代码网上找到的，是一个简单通信录的演示，可是我发现这个通信录在输入4条以上数据后，选择LIST列出所有项后，就会死循环地重复列某一个记录，请教该如何修改？
   http://bbs.bccn.net/images/smilies/emot/em09.gif','Image‘);” onmouseover=”this.style.cursor=’hand’” onmouseout=”this.style.cursor=”” src=”http://bbs.bccn.net/images/smilies/emot/em09.gif” border=”0″ />  谢谢了！
   /*————————————————–华丽的分割线———————————————————————-*/

   #include <stdio.h>
   #include <stdlib.h>
   struct address{
     char name[20];
     char street[20];
     char city[10];
     char state[10];
     char zip[7];
     struct address *next;
     struct address *prior;
     }list_entry;

   struct address *start;
   struct address *last;

   void enter();
   void display();
   void search();
   void save();
   void load();
   void list();

   struct address *find(char *name);
   struct address *dls_store(struct address *,struct address *);

   main()
   {
   clrscr();
   start=last=NULL;
   load();
   for (;;){
     switch(menu_select()){
       case 1:enter();break;
       case 2:delete();break;
       case 3:list();break;
       case 4:search();break;
       case 5:save();break;
       case 6:exit(0);
       }
     }
   }

   menu_select()
   {
   char c;
   printf(“1.Enter\n”);
   printf(“2.Delete\n”);
   printf(“3.List\n”);
   printf(“4.Search\n”);
   printf(“5.Save\n”);
   printf(“6.Quit\n”);
   do{
     printf(“\nEnter you choice:”);
     c=getche();
     }while (c<’0′||c>’6′);
   return c-48;
   }

   void enter()
   {
   struct address *info;
   for (;;){
     info=(struct address *)malloc(sizeof(list_entry));
     if (!info){
       printf(“\nout of memory”);
     return;
     }
     inputs(“\nenter name:”,info->name,19);
     if (!info->name[0]) break;
     inputs(“enter street:”,info->street,19);
     inputs(“enter city:”,info->city,9);
     inputs(“enter state:”,info->state,9);
     inputs(“enter zip:”,info->zip,6);
     start=dls_store(info,start);
     }
   }

   inputs(char *prompt,char *s,int count)
   {
   char p[255];
   do{
     printf(prompt);
     gets(p);
     if (strlen(p)>count) printf(“\ntoo long\n”);
     }while (strlen(p)>count);
     strcpy(s,p);
   }

   struct address *dls_store(struct address *i,struct address *top)
   {
   struct address *old,*p;
   if (last==NULL){
     i->next=NULL;
     i->prior=NULL;
     last=i;
     return i;
     }
   p=top;
   old=NULL;
   while(p){
     if (strcmp(p->name,i->name)<0){
       old=p;p=p->next;
       }
     else{
       if(p->prior){
         p->prior->next=i;
         i->next=p;
         i->prior=p->prior;
         p->prior=i;
         return top;
         }
       i->next=p;
       i->prior=NULL;
       p->prior=i;
       return i;
       }
     }
     old->next=i;
     i->next=NULL;
     i->prior=old;
     last=i;
     return start;
   }

   delete()
   {
   struct address *info;
   char s[80];
   printf(“enter name:”);
   gets(s);
   info=find(s);
   if (info) {
     if (start==info){
       start=info->next;
       if (start)
         start->prior=NULL;
       else
         last=NULL;
       }
     else{
       info->prior->next=info->next;
       if(info!=last)
         info->prior->next=info->prior;
       else
         last=info->prior;
       }
     free(info);
     }
   }

   struct address *find(char *name)
   {
   struct address *info;
   info=start;
   while(info){
     if(!strcmp(name,info->name)) return info;
     info=info->next;
     }
   printf(“name not found\n”);
   return NULL;
   }

   void list()
   {
   struct address *info;
   info=start;
   printf(“\n%-20s%-20s%-10s%-10s%-6s\n”,
     ”姓名”,”街道”,”城市”,”省”,”邮编”);
   while(info){
     display(info);
     info=info->next;
     }
   printf(“\n\n”);
   }

   void display(struct address *info)
   {
   printf(“%-20s%-20s%-10s%-10s%-6s\n”,
     info->name,info->street,info->city,info->state,info->zip);
   }

   void search()
   {
   char name[40];
   struct address *info,*find();
   printf(“enter name to find:”);
   gets(name);
   info=find(name);
   if(!info)
     printf(“not found\n”);
   else
     display(info);
   }

   void save()
   {
   struct address *info;
   FILE *fp;
   if((fp=fopen(“mlist”,”wb”))==NULL){
     printf(“can not open file\n”);
     exit(1);
     }
   printf(“\nSaving file\n”);
   info=start;
   while(info){
     fwrite(info,sizeof(struct address),1,fp);
     info=info->next;
     }
   fclose(fp);
   }

   void load()
   {
   struct address *info,*temp=NULL;
   FILE *fp;
   if((fp=fopen(“mlist”,”rb”))==NULL){
     printf(“can not open file\n”);
     return;
     }
   while(start){
     info=start->next;
     free(info);
     start=info;
     }
   printf(“\nLoading file\n”);
   start=(struct address *)malloc(sizeof(struct address));
   if(!start){
     printf(“out of memory!\n”);
     return;
     }
   info=start;
   while(!feof(fp)){
     if(1!=fread(info,sizeof(struct address),1,fp)) break;
     info->next=(struct address *)malloc(sizeof(struct address));
     if (!info->next){
       printf(“out of memory\n”);
       return;
       }
     info->prior=temp;
     temp=info;
     info=info->next;
     }
   temp->next=NULL;
   last=temp;
   start->prior=NULL;
   fclose(fp);
   }