#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <ctype.h>
#include <string.h>

struct address {
       char name[30] ;
       char street[30] ;
       char city[20] ;
       char state[3] ;
       char zip[10] ;
       struct address *next ;
       struct address *prior ;
} list_entry ;

struct address *start ;
struct address *last ;

void enter() , display() , search() ;
void save()  , load()    , list() , del();
void display(struct address *info, int *row);

struct address *find(char *);
int menu_select();
struct address *store(struct address *, struct address *);

int main ()
{
       start = last = NULL ;
       for(;;) {
	    switch(menu_select()) {
	       case 1:  enter();  break ;
	       case 2 : del();    break ;
	       case 3:  list() ;  break ;
	       case 4:  search(); break ;
	       case 5:  save();   break ;
	       case 6:  load();   break ;
	       case 7:  exit(0) ;
	    }//end of switch
       }//end of for
}//end of main
//****************
int menu_select()
{
      char s[5];
      clrscr() ;
      gotoxy(25, 4) ;
      printf("1. enter a name ") ;
      gotoxy(25, 6) ;
      printf("2. delete a name ") ;
      gotoxy(25, 8) ;
      printf("3. list all files ") ;
      gotoxy(25, 10) ;
      printf("4. search ") ;
      gotoxy(25, 12) ;
      printf("5. save the file  ") ;
      gotoxy(25, 14) ;
      printf("6. load the file  ") ;
      gotoxy(25, 16) ;
      printf("7. quit ") ;
      do {
	  gotoxy(20, 18) ;
	  printf("enter your select(1-7):");
	  gets(s);
      } while (atoi(s) < 0 || atoi(s) > 7) ;
      return atoi(s) ;
}
//*********************
void enter ()
{
   struct address *info ;
   int i ;
   char ch ;
   clrscr() ;
   gotoxy(3, 2) ;
   printf("   name        street     city     state    zip");
   gotoxy(3, 3) ;
   printf(" ------------ -------- ");
   printf("--------   -----  ------- ");
   i = 4 ;
   for (;;) {
     info = (struct address *)malloc(sizeof(list_entry)) ;
     if(!info) {
	printf("\n out of memory. press a key ") ;
	getch();
	return ;
     }
     gotoxy(3, i) ;
     gets(info -> name) ;
     if (!info -> name[0]) {
	  gotoxy(15, i + 1) ;
	  printf("press a key to continue");
	  getch() ;
	  break ;
     }//end of if
     gotoxy(18, i);
     gets(info -> street) ;
     gotoxy(28, i) ;
     gets(info -> city) ;
     gotoxy(38, i) ;
     gets(info -> state) ;
     gotoxy(45, i) ;
     gets(info -> zip) ;
     i++ ;
     start = store(info, start) ;
     } /* entry loop */
   }
//**************
struct address *store(struct address *i, struct address *top)
{
   struct address *old, *p ;
   if(last == NULL) {
	i -> next = NULL ;
	i -> prior = NULL ;
	start = i;
	last = i ;
	return i ;
   }
   p = top ;
   old = NULL ;
   while (p != NULL) {
       if(strcmp(p -> name, i -> name) < 0) {
	      old = p ;
	      p = p -> next ;
       }//end of if
       else {
	     if (p -> prior) {
		  p -> prior -> next=i ;
		  i -> next=p ;
		  i -> prior=p -> prior;
		  p -> prior=i ;
		  return top ;
	     }//end of if
	     i -> next = p ;
	     i -> prior = NULL ;
	     p -> prior = i ;
	     return i ;
       }//end of if
   } // end of while
   old -> next = i ;
   i -> next = NULL ;
   i -> prior = old ;
   last = i ;
   return start ;
}
//******************
void del()
{
   struct address *info;
   char name[80];
   gotoxy(20, 20) ;
   printf(" enter name for delete : ") ;
   gets(name) ;
   info = find(name) ;
   if(info == NULL) {
       gotoxy(10, 20) ;
       printf(" name not found! press a key to continue.");
       getch() ;
   }
   if (info)
     if (start == info)
	{
	  start = info -> next ;
	  if(start)
	     start -> prior = NULL ;
	  else
	     last = NULL ;
	} //end of if
     else  {
	   info -> prior -> next = info -> next;
	   if(info != last)
		 info -> next -> prior = info -> prior;
	   else
		last = info -> prior ;
     } //end of else
     free(info) ;
     gotoxy(10,20) ;
     printf("name deleted, press a key to continue.");
     getch() ;
}
//*******************************
struct address *find(char *name)
{
     struct address *info ;
     info = start ;
     while(info != NULL) {
	if (strcmp(name, info -> name) == 0)
	   return info;
	info = info -> next ;
     }
     return NULL ;
}
//*****************
void list ()
{
    struct address *info ;
    int i ;
    info = start ;
    clrscr() ;
    gotoxy(3, 2) ;
    printf("   name        street     city     state    zip");
    gotoxy(3, 3) ;
    printf(" ------------ --------  -");
    printf("-------   -----  ------- ");
    i = 4 ;
    while(info != NULL) {
	display(info, &i) ;
	info = info -> next ;
    }
    gotoxy(15, i + 2) ;
    printf("press a key to continue.");
    getch() ;
}
//*******************
void display(struct address *info, int *row)
{
	  gotoxy(3, *row) ;
	  printf("%s", info -> name) ;
	  gotoxy(18, *row) ;
	  printf("%s", info -> street) ;
	  gotoxy(28, *row) ;
	  printf("%s", info -> city) ;
	  gotoxy(38, *row) ;
	  printf(info -> state) ;
	  gotoxy(47, *row) ;
	  printf(info -> zip) ;
	  *row = *row + 1 ;
}
//**************************
void search()
{
     char name[40] ;
     int i ;
     struct address *info;
     gotoxy(20, 20) ;
     printf(" enter name to find : ");
     gets(name) ;
     info = find(name) ;
     if(info == NULL) {
	  gotoxy(10, 20) ;
	  printf(" name not found! press a key to continue.");
	  getch() ;
     }//end of if
     else  {
	  clrscr() ;
	  gotoxy(3, 2) ;
	  printf("   name        street   city     state   zip");
	  gotoxy(3, 3) ;
	  printf(" ------------ -------");
	  printf("-  --------   -----  ------- ") ;
	  i = 4 ;
	  display(info ,&i) ;
	  gotoxy(15, i + 2) ;
	  printf("press a key to continue.");
	  getch() ;
     }//end of else
}
//*********************
void save()
{
    struct address *info ;
    FILE *fp ;
    if((fp = fopen("l.dat","wb")) == NULL)  {
	printf("\n cannot open file. ") ;
	getch();
	exit(1) ;
    }//end of if
    gotoxy(20, 20) ;
    printf("<< saving file >>") ;
    info = start ;
    while(info) {
      fwrite(info, sizeof(struct address), 1, fp);
      info = info -> next ;
    }//end of while
    fclose(fp) ;
    gotoxy(15, 22) ;
    printf("file successfuly saved press a key...") ;
    getch() ;
}
//********************
void load ()
{
    struct address *info , *temp = NULL;
    FILE *fp ;
    fp = fopen("l.dat","rb") ;
    if(fp == NULL)  {
	printf("\n cannot open file.");
	getch();
	exit(1) ;
    }
    while(start) {
      info = start -> next ;
      free(info) ;
      start = info ;
    }
    gotoxy(20,20) ;
    printf(" << loading file  >> ") ;
    start = NULL ;
    while (!feof(fp)) {
	  info = (struct address *)
		malloc(sizeof(struct address)) ;
	  if(1 != fread(info, sizeof(struct address), 1, fp))
		   break ;
	  if(start == NULL)  {
	      temp = start = info ;
	      info -> prior = NULL ;
	      info -> next = NULL ;
	  }//end of if
	  else  {
	      info -> next = NULL ;
	      temp -> next = info ;
	      info -> prior = temp ;
	      temp = info;
	  }
    }//end of while
    last = temp ;
    fclose(fp) ;
    gotoxy(15,22) ;
    printf("file successfuly loaded press a key ...") ;
    getch();
}