링크드리스트 이용한 도서관리 프로그램

#include "stdafx.h"

typedef struct _book
{
 char BookName[50];
 struct _book *next;
 struct _book *prev;
}BookList;

BookList *Head, *Tail;

void InitBookList()
{
 Head = (BookList*)malloc(sizeof(BookList));
 Tail = (BookList*)malloc(sizeof(BookList));
 Head->next = Tail;
 Tail->prev = Head;
}

void AddBookList(char *str)
{
 BookList *add = (BookList*)malloc(sizeof(BookList));
 
 strcpy(add->BookName, str);
 
 Tail->prev->next = add;
 add->prev = Tail->prev;
 
 add->next = Tail;
 Tail->prev = add;
}

void DelBookList(char *str)
{
 BookList *del,*loof;
 loof = Head->next;
 while(loof != Tail)
 {
  if(strcmp(loof->BookName, str) == 0)
  {
   del = loof;
   loof->prev->next = loof->next;
   loof->next->prev = loof->prev;
   
   free(del);
   return;
  }
  loof = loof->next;
 }
}

void SearchBookList(char *str)
{
 BookList *loof;
 loof = Head->next;
 while(loof != Tail)
 {
  if(strcmp(loof->BookName, str) == 0)
  {
   printf("%s을 찾았습니다\n", str);  
   return;
  }
  loof = loof->next;
 }
 printf("%s을 찾지못했습니다\n", str);
}

void EditBookList(char *str)
{
 BookList *loof;
 loof = Head->next;
 while(loof != Tail)
 {
  if(strcmp(loof->BookName, str) == 0)
  {
   printf("바꿀 책이름 입력:");
   gets(loof->BookName);
   return;
  }
  loof = loof->next;
 }
}

void ShowBookList()
{
 BookList *loof;
 loof = Head->next;
 printf("책 제목\n");
 while(loof != Tail)
 {
  printf("%s\n", loof->BookName);
  loof = loof->next;
 }
}

void SaveData()
{
 BookList *loof;
 FILE *fp = fopen("book.txt", "w");
 loof = Head->next;

 while(loof != Tail)
 {
  fprintf(fp,"%s\n", loof->BookName);
  loof = loof->next;
 }
 fclose(fp);
}

void LoadData()
{
 FILE *fp = fopen("book.txt","r");
 char str[50];
 
 if(fp == NULL) return;
 
 while(1)
 {
  if(fgets(str,50,fp) == NULL) break;
  if(strlen(str) > 1)
  {
   str[strlen(str)-1] = NULL;
   AddBookList(str);
  }
 }
 
 fclose(fp);
}

int main()
{
 int num;
 char str[50];
 
 InitBookList();
 LoadData();
 
 while(1)
 {
  do{
   //system("cls");
   printf("###########\n");
   printf("1. 도서추가\n2. 도서수정\n3. 도서리스트\n4.도서 검색\n5.도서 삭제\n6.종 료\n");
   printf("###########\n");
   printf("숫자를 입력하세요 :");
   scanf("%d", &num);
   fflush(stdin);  
  }while(num<=0||num>6);
  switch(num)
  {
  case 1:  
   printf("추가할 책 이름 입력:");
   gets(str);
   AddBookList(str);
   break;
  case 2:
   printf("수정할 책 이름 입력:");
   gets(str);  
   EditBookList(str);
   break;
  case 3:  
   ShowBookList();
   break;
  case 4:
   printf("검색할 책 이름 입력:");
   gets(str);  
   SearchBookList(str);
   break;
  case 5:
   printf("삭제할 책 이름 입력:");
   gets(str);  
   DelBookList(str);
   break;
  case 6:
   SaveData();
   return 0;
   break;
   
  }
 }
 return 0;
}