Лабораторная работа3

//Inclusion of library functions of C++
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>
//definition of structure link used to form my book list
typedef struct link
	 {
	  char books[10];
	  char firstname[13];
	  char surname[13];
	  char date_pub[9];
	  int booknum;
	  int hall;
	  int num_books;
	  struct link *backward;
	  struct link *forward;
	 }DATA ;     //link defined to DATA

//definition of the global variables used.
DATA *info,*first,*fur,*crec;
int i,j,n,num,srch;
char halls[4][11]={"Science","Literature","History","Law"};

DATA *copyelsearch(DATA *scol);//Copy individual fields(subfunction of search_for)

void main(void)
{
  first=NULL;
//description of the functions used

  void putd_text(int x,int y,char *word);//used to put strings to a particular position
  void intowin (int x,int y,int d,int w,char *title,char *str,int len);//collects strings to window

  int  testnumber(int num,int lowl, int upl);//input number of lib. no. & hall no. & hall no. &rejects letters and numbers <=0
  DATA *inp1(); //input of data to book's list
  void outmain(DATA *rec);//outputs book's list ,main interface with user
  int outsm(DATA *rec);//outputs data book's list and helps to simplify processing
  DATA *inpadd(DATA *col);//create or adds new elements to data book's list
  DATA *del(DATA *ncol);//deletes a specified element from data book's list
  DATA *search_for(DATA *scol);//searches for element/s in data book's list
  void savenew(DATA*tosav);//saves data book's list into a named file
  DATA *loadfile();//opens file to read saved data book's list


  char ch,mh;
    clrscr();
    _setcursortype(_NOCURSOR);
    textbackground(BLACK);
    window(10,5,70,20);     //welcome window
    textbackground(BLUE);
    textcolor(WHITE);
    gotoxy(1,1);
    cprintf("ЙНННННННННННННННННННННННННННННННННННННННННННННННННННННННН»"); gotoxy(1,2);
    cprintf("¶     St.Petersburg state Electrotechnical University    ¶"); gotoxy(1,3);
    cprintf("¶           Department of Computer Technology            ¶"); gotoxy(1,4);
    cprintf("¶                    COURSEWORK                          ¶"); gotoxy(1,5);
    cprintf("¶                                                        ¶"); gotoxy(1,6);
    cprintf("¶  written by:                                           ¶"); gotoxy(1,7);
    cprintf("¶                                                        ¶"); gotoxy(1,8);
    cprintf("З  1                                                     ¶"); gotoxy(1,9);
    cprintf("ИННННННННННННННННННННННННННННННННННННННННННННННННННННННННј"); gotoxy(1,10);
    cprintf("             ..... PLEASE PRESS ANY KEY .....             ");
    fflush(stdin);
    getch();
    clrscr();
    window(1,1,80,25);
    textbackground(BLACK);
    clrscr();

    //MAIN MENU
    int l=1;
      do
	{
	 clrscr();
	 gotoxy(10,6);
	 printf("MAIN MENU");gotoxy(10,7);
	 printf("PLEASE MAKE A CHOICE");gotoxy(10,10);
	 printf("1. CREATE LIST");gotoxy(10,11);
	 printf("2. ADD NEW ELEMENT(S)");gotoxy(10,12);
	 printf("3. DELETE A SPECIFIC ELEMENT");gotoxy(10,13);
	 printf("4. SAVE IN FILE");gotoxy(10,14);
	 printf("5. OPEN FILE");gotoxy(10,15);
	 printf("6. SEARCH");gotoxy(10,16);
	 printf("7. EXIT");
	 switch(getch())
	   {
	    case '1':
	      {
	       clrscr();
	       int dl=1,p=0;
	       if(first)
		   fflush(stdin);
		   if(dl==1)
		    {
		     printf("\n Give Number of books to be considered...");
		     printf("\n  Must be a Number greater than 0 ");
		     printf("\n           NO:= ");
		     fflush(stdin);
		     if((scanf("%d",&n))&&n>0)
		      p=0;
		     else
		      if((n<=0)||(!scanf("%d",&n)))
		       {
			do
			 {
			  printf("\n ERROR OF INPUT !!!!! \n PLEASE TRY AGAIN");
			  printf("\n\n  Must be a NUMBER greater than 0 ");
			  printf("\n             NO:= ");
			  fflush(stdin);
			  if((scanf("%d",&n))&&n>0)
			   p=0;
			  else
			   if((n<=0)||(!scanf("%d",&n)))
			    p=1;
			 } while(p==1);
		       }
		     fflush(stdin);
		     crec=inp1();
		     outmain(crec);
		     fflush(stdin);
		     getch();
		     clrscr();
		    }

		break;
	      }
	    case '2':
	      {
	       clrscr();
	       crec=inpadd(crec);
	       outmain(crec);
	       getch();
	       break;
	      }
	    case '3':
	      {
		clrscr();
		crec=del(crec);
		if(crec==NULL)
		 {
		  printf("\nYou have just deleted the final element in your list, but you");
		  printf("\n can still create a new list or open one from existing files");
		  getch();
		  clrscr();
		 }
		else
		 {
		  outmain(crec);
		 }

		getch();
		break;
	      }
	    case '4':
	      {
	       clrscr();
	       savenew(crec);
	       getch();
	       break;
	      }
	    case '5':
	      {
	       clrscr();
	       crec=loadfile();
	       getch();
	       clrscr();
	       outmain(crec);
	       getch();
	       break;
	      }
	    case '6':
	      {
	       clrscr();
	       DATA *first11,*crec11;
	       first11=first;
	       crec11=crec;

	       crec=search_for(crec);
	       if(crec)
		 {
		  outmain(crec);
		  printf("\nTHIS IS YOUR SEARCH \n");
		  printf("\nPRESS ANY KEY TO CONTINUE \n");
		  getch();
		  clrscr();
		 }

	       first=first11;
	       crec=crec11;
	       getch();
	       break;
	      }
	    case '7':
	      {
		clrscr();
		gotoxy(5,11);
		cprintf("ЙНННННННННННННННННННННННННННННННННННННННННННННННННННННННН»"); gotoxy(5,12);
		cprintf("¶           YOU WILL LOSE ALL UNSAVED INFO               ¶"); gotoxy(5,13);
		cprintf("¶                    CONFIRM EXIT                        ¶"); gotoxy(5,14);
		cprintf("¶                                                        ¶"); gotoxy(5,15);
		cprintf("¶            (Y)-> YES         (N)-> CANCEL              ¶"); gotoxy(5,16);
		cprintf("ИННННННННННННННННННННННННННННННННННННННННННННННННННННННННј"); gotoxy(5,20);
		cprintf("           ..... PLEASE ENTER YOUR CHOICE .....           ");
		fflush(stdin);
		l=getch();
		break;
	      }
	     default:
	      {
	       printf("\nPlease input a number from 1 to 4\n");
	       printf("Press any key to continue");
	       getch();
	       break;
	      }
	   }
	}while(l!='y'&& l!='Y');
  free(first);
  //getch();
}

//function which verifies integer value of lib.no. & hall no. & book no.
int testnumber(int num,int lowl,int upl)
 {
  int p=0;
  if(( scanf("%d",&num))&&num>lowl&&num<upl)
   p=0;
  else
   if(num<=lowl||num>=upl||(!scanf("%d",&num)))//rejects non integers 0 and -ve numbers
    {
     do
      {
       printf("\n ERROR OF INPUT !!!!! PLEASE TRY AGAIN");
       printf("\n Number must be btw %d and %d n:= ",lowl,upl);
       fflush(stdin);
       if(( scanf("%d",&num))&&num>lowl&&num<upl)
	p=0;
       else
	if(num<=lowl||num>=upl||(!scanf("%d",&num)))
	 p=1;
      } while(p==1);
    }
   return(num);
 }


//function which creates operating list for books
DATA *inp1()
 {
  first=fur=info=NULL; //removes previous members of list
  for(i=0;i<n;i++)
   {
    if(first==NULL)//creates head element of list
     {
      info=(DATA*)malloc(sizeof(DATA));
      printf("\n Give title of no %d Book: ",i+1);
      scanf("%s",info->books);
      fflush(stdin);
      printf("\n Give name of author: ");
      scanf("%s",info->firstname);
      fflush(stdin);
      printf("\n Give surname of author: ");
      scanf("%s",info->surname);
      fflush(stdin);
      printf("\n Date when book was published: ");
      scanf("%s",info->date_pub);
      fflush(stdin);
      printf("\n Give book's identity number: ");
      info->booknum=testnumber(num,0,999);
      fflush(stdin);
      printf("\n 1-Science , 2-Literature , 3-History , 4-Law");
      printf("\n Give hall number to which the book belongs to: ");
      info->hall=testnumber(num,0,5)-1;
      fflush(stdin);
      printf("\n Give number of copies of particular book: ");
      info->num_books=testnumber(num,0,9999);
      fflush(stdin);
      info->backward=NULL;
      info->forward=NULL;
      first=info;
     }
    else
     {
      fur=info;//creates subsequent elements
      info=(DATA*)malloc(sizeof(DATA));
      printf("\n Give title of no %d Book: ",i+1);
      scanf("%s",info->books);
      fflush(stdin);
      printf("\n Give name of author: ");
      scanf("%s",info->firstname);
      fflush(stdin);
      printf("\n Give surname of author: ");
      scanf("%s",info->surname);
      fflush(stdin);
      printf("\n Date when book was published: ");
      scanf("%s",info->date_pub);
      fflush(stdin);
      printf("\n Give book's identity number: ");
      info->booknum=testnumber(num,0,999);
      fflush(stdin);
      printf("\n 1-Science , 2-Literature , 3-History , 4-Law");
      printf("\n Give hall number to which the book belongs to: ");
      info->hall=testnumber(num,0,5)-1;
      fflush(stdin);
      printf("\n Give number of copies of particular book: ");
      info->num_books=testnumber(num,0,9999);
      fflush(stdin);
      info->backward=fur;
      info->forward=NULL;
      fur->forward=info;
     }
   }
  info=first;
  return(info);
 }


//function for main output of programme for books
void outmain(DATA *rec)
 {
  clrscr();
  gotoxy(15,20);
  printf("   ESC       |          ANY OTHER KEY     ");
  gotoxy(15,21);
  printf(" TO EXIT     |      TO RETURN TO MAIN MENU");
  n=0;
  if(!rec)
   n=10;
  else
   {
    do
     {
      n++;
      rec=rec->forward;
     } while(rec!=NULL);
    rec=first;
    n=n+9;
   }
  gotoxy(1,2);
  printf("BOOK       NAME        SURNAME    DATE      BOOK # HALL  #     No. books");
  if(rec)
   {
    i=3;
    do
     {
      gotoxy(1,i);
      printf("%-11s",rec->books);
      printf("%-12s",rec->firstname);
      printf("%-11s",rec->surname);
      printf("%-10s",rec->date_pub);
      printf("%-7d",rec->booknum);
      printf("%-12s",halls[rec->hall]);
      printf("%-9d",rec->num_books);
      rec=rec->forward;
      i++;
     } while(rec!=NULL);
	 rec=first;
   }
  else
   {
    gotoxy(15,1);
    printf("EMPTY LIST PLEASE INPUT DATA FIRST!!!");
   }
 }

//frequently used function for output of selected strings
void putd_text(int x,int y,char *word)
 {
  gotoxy(x,y);
  puts(word);
 }

//function which outputs data for books into functions that process the data
int outsm(DATA *rec)
 {
  j=1;
  if(!rec)
   printf("\n NO ELEMENT IN YOUR LIST PLEASE .....\n");
  else
   do
    {
     printf("\n No %d book:",j);
     printf(" %-12s",rec->books);
     printf(" %-12s",rec->firstname);
     printf(" %-12s",rec->surname);
     printf(" %5s",rec->date_pub);
     printf(" %-4d",rec->booknum);
     printf(" %11s",halls[rec->hall]);
     printf(" %-5d",rec->num_books);
     j++;
     rec=rec->forward;
    } while(rec!=NULL);
   rec=first;
   return (j);
 }

//function which adds new elements to data book's list after the first elemant
DATA *inpadd(DATA *ncol)
 {
  int m,p=0;
  if(ncol==NULL)
   {
    printf("\n List is EMPTY you'll be creating one by adding new elements\n ");
    printf("\n Give number of books to be considered...");
    printf("\n  Must be a number greater than 0 ");
    printf("\n             NO:= ");
    fflush(stdin);
    if((scanf("%d",&n))&&n>0)
     p=0;
    else
     if((n<=0)||(!scanf("%d",&n)))
      {
       do
	{
	 printf("\n ERROR OF INPUT !!!!! PLEASE TRY AGAIN");
	 printf("\n  Must be a NUMBER greater than 0 ");
	 printf("\n         NO:= ");
	 fflush(stdin);
	 if((scanf("%d",&n))&&n>0)
	 p=0;
	 else
	  if((n<=0)||(!scanf("%d",&n)))
	   p=1;
	} while(p==1);
      }
    fflush(stdin);
    ncol=inp1();
   }
  else
   {
    clrscr();
    p=0;
    printf("\n Here is the list you have chosen to add to:\n ");
    outsm(ncol);
    fflush(stdin);
    printf("\n Give number of new books to be added ....");
    printf("\n  Must be a NUMBER greater than 0 ");
    printf("\n               NO:= ");
    fflush(stdin);
    if((scanf("%d",&m))&&(m>0))
     p=0;
    else
     if((m<=0)||(!scanf("%d",&m)))
      {
       do
	{
	 printf("\n ERROR OF INPUT !!!!! PLEASE TRY AGAIN");
	 printf("\n  Must be a NUMBER greater than 0 n:= ");
	 printf("\n          NO:= ");
	 fflush(stdin);
	 if((scanf("%d",&m))&&(m>0))
	  p=0;
	 else
	  if((m<=0)||(!scanf("%d",&m)))
	   p=1;
	} while(p==1);
      }
   fflush(stdin);
   ncol=first;
   for(i=0;i<m;i++)
    {
     info=(DATA*)malloc(sizeof(DATA));
     printf("\n Give title of no %d Book: ",i+1);
     scanf("%s",info->books);
     fflush(stdin);
     printf("\n Give name of author: ");
     scanf("%s",info->firstname);
     fflush(stdin);
     printf("\n Give surname of author: ");
     scanf("%s",info->surname);
     fflush(stdin);
     printf("\n Date when book was published: ");
     scanf("%s",info->date_pub);
     fflush(stdin);
     printf("\n Give book's identity number: ");
     info->booknum=testnumber(num,0,999);
     fflush(stdin);
     printf("\n 1-Science , 2-Literature , 3-History , 4-Law");
     printf("\n Give hall number to which the book belongs to: ");
     info->hall=testnumber(num,0,5)-1;
     fflush(stdin);
     printf("\n Give number of copies of particular book: ");
     info->num_books=testnumber(num,0,9999);
     fflush(stdin);
     info->forward=ncol->forward;
     ncol->forward->backward=info;
     info->backward=ncol;
     ncol->forward=info;
    }
   }
  return(ncol);
 }

//function which deletes a specified element from data book's list
DATA *del(DATA *ncol)
 {
  int x,y,p=0;
  clrscr();
  if(!ncol)
   return(NULL);
  else
   {
    ncol=first;
    printf("\n Here is the list you want to delete from :\n ");
    //function outsm gives user the opportunity to choose
    //the number of the book he wants deleted
    //however choice must be only from those on screen!!!
    y=outsm(ncol);
    printf("\n Please give the BOOK'S NUMBER you want deleted");
    printf("\n  must be a NUMBER from those listed above ");
    printf("\n              No:= ");
    fflush(stdin);
    if((scanf("%d",&x))&&(x>0)&&(x<=y-1))
     p=0;
    else
     if((x<=0)||(x>y-1)||(!scanf("%d",&x)))
      {
       do
	{
	 printf("\n ERROR OF INPUT !!!!! PLEASE TRY AGAIN");
	 printf("\n  Must be a NUMBER from those listed above ");
	 printf("\n          No:= ");
	 fflush(stdin);
	 if((scanf("%d",&x))&&(x>0)&&(x<=y-1))
	  p=0;
	 else
	  if((x<=0)||(x>y-1)||(!scanf("%d",&x)))
	   p=1;
	} while(p==1);
      }
    fflush(stdin);
    for(j=0;j<x-1;j++)
    ncol=ncol->forward;
    if(first==ncol)
     first=ncol->forward;
     ncol->backward->forward=ncol->forward;
     ncol->forward->backward=ncol->backward;
     free(ncol);
     ncol=first;
     return(ncol);
   };
 }



//function used to write strings into window
void intowin(int x,int y,int d,int w,char *title,char *str,int len)
 {
  clrscr();
  void *destin;
  int i;
  char *inp;
  int xtmp,ytmp;
  inp=(char *)malloc(sizeof(char)*30);
  destin=(void *)malloc(2*d*w);
  xtmp=wherex();
  ytmp=wherey();
  gettext(x,y,x+d-1,y+w-1,destin);
  textcolor(WHITE);
  clrscr();
  //-------------
  //Draws border:
  gotoxy(x,y);
  printf("Ъ");
  for(i=0;i<d-2;i++)
  printf("Д");
  printf("ї");
  for(i=0;i<w-2;i++)
   {
    gotoxy(x+d-1,y+i+1);
    printf("і");
   }
  gotoxy(x+d-1,y+w-1);
  printf("Щ");
  gotoxy(x+1,y+w-1);
  for(i=0;i<d-2;i++)
   printf("Д");
  for(i=0;i<w-2;i++)
   {
    gotoxy(x,y+i+1);
    printf("і");
   }
  gotoxy(x,y+w-1);
   printf("А");
  //-------------
  //fixes title at topcenter of window
  gotoxy(x+(d-strlen(title))/2,y);
  printf("%s",title);
  inp[0]=len+1;
  strcpy(str,gets(inp));
  puttext(x,y,x+d-1,y+w-1,destin);
  free(destin);
  free(inp);
  gotoxy(xtmp,ytmp);
 }

//function for saving selected data book's list to file
void savenew(DATA*tosav)
 {
  FILE *fp;
  int cre=0;
  char str[30];
  intowin(10,10,40,3,"SAVE AS",str,30);
  fflush(stdin);
  if((fp=fopen(str,"rb"))==NULL)
   cre=1;
  else
   {
    window(1,1,80,25);
    int an;
    gotoxy(10,10);printf("FILE ALREADY EXISTS OVERWRITE IT");
    gotoxy(10,12);printf("ENTER");
    gotoxy(10,13);printf("CANCEL");
    gotoxy(10,15);printf("Please enter your choice :");
    scanf("%d",&an);
    if(an==2)
     an=0;
    else
     cre=1;
   }
  if(cre==1)
   {
    if((fp=fopen(str,"wb"))==NULL)
     {
      gotoxy(10,15);
      textcolor(RED);
      cprintf("SYSTEM ERROR:CAN'T OPEN FILE - %s",str);
      textcolor(YELLOW);
      char *erob="PRESS ANY KEY TO RETURN TO MENU";
      putd_text(10,16,erob);
      getch();
      clrscr();
      textbackground(BLACK);
      textcolor(WHITE);
      fflush(stdin);
     }
    else
     {
      n=0;
      do
       {
	n++;
	tosav=tosav->forward;
       } while(tosav!=NULL);
    fwrite(&n,sizeof(int),1,fp);
    tosav=first;
    for(i=0;i<n;i++)
     {
      fwrite(tosav,sizeof(DATA)-2*sizeof(struct link*),1,fp);
      tosav=tosav->forward;
     }
    fclose(fp);
    gotoxy(10,15);
    textcolor(RED);
    cprintf("FILE { %s } SAVED.",str);
    gotoxy(10,16);
    textcolor(YELLOW);
    cprintf("PLEASE PRESS ANY KEY TWICE TO RETURN TO MENU");
    getch();
    clrscr();
    textbackground(BLACK);
    textcolor(WHITE);
   }
  }
 }

//function which reads data book's list from file
DATA *loadfile()
 {
  FILE *fp;
  char rstr[30];
  clrscr();
  //intowin(10,10,40,3,"GIVE FILE NAME",rstr,30);
  gotoxy(5,11);
  printf("ЙННННННННННННННННННННННННННННННН»"); gotoxy(5,12);
  printf("¶       GIVE FILE NAME:         ¶"); gotoxy(5,13);
  printf("¶                               ¶"); gotoxy(5,14);
  printf("¶                               ¶"); gotoxy(5,15);
  printf("ИНННННННННННННННННННННННННННННННј"); gotoxy(5,17);
  printf("... PLEASE ENTER YOUR CHOICE ... ");
  //clrscr();
  textcolor(YELLOW);
  gotoxy(15,14);
  cscanf("%s",&rstr);
  textbackground(BLACK);
  textcolor(WHITE);
  clrscr();
  fflush(stdin);
  if((fp=fopen(rstr,"rb"))==NULL)
   {
    gotoxy(10,15);
    textcolor(RED);
    cprintf("SYSTEM ERROR:CAN'T OPEN FILE -{ %s }",rstr);
    gotoxy(10,16);
    textcolor(YELLOW);
    cprintf("PLEASE PRESS ANY KEY TO CONTINUE");
    getch();
    clrscr();
    textbackground(BLACK);
    textcolor(WHITE);

    return(NULL);
   }
  //creates memory space and new list from the read data
  else
   {
    fread(&n,sizeof(int),1,fp);
    first=fur=info=NULL;
    for(i=0;i<n;i++)
     {
      if(first==NULL)
       {
	info=(DATA*)malloc(sizeof(DATA));
	fread(info,sizeof(DATA)-2*sizeof(struct link*),1,fp);
	info->backward=NULL;
	info->forward=NULL;
	first=info;
       }
      else
       {
	fur=info;
	info=(DATA*)malloc(sizeof(DATA));
	fread(info,sizeof(DATA)-2*sizeof(struct link*),1,fp);
	info->backward=fur;
	info->forward=NULL;
	fur->forward=info;
       }
     }
    info=first;
    fclose(fp);
    _setcursortype(_NORMALCURSOR);
    clrscr();
    return(info);//returns a new list from read data
   }
 }


//function which searches for book/s of given properties
DATA *search_for(DATA *scol)
 {
  DATA **searcher,*sfirst;
  char sname[17],ssurname[17],sbooks[17],sdate_pub[19];
  int x,y,shall,snum_books,sbooknum;
  clrscr();
  if(!scol)
   {
    return(NULL);
   }
  else
   {
    scol=first;
    n=0;
    do
     {
      n++;
      scol=scol->forward;
     } while(scol!=NULL);
    scol=first;
    clrscr();
	//sub menu for search
    int an;
    gotoxy(10,10);
    printf("   SEARCH BY");gotoxy(10,12);
    printf("1. ALL");gotoxy(10,13);
    printf("2. BOOKS");gotoxy(10,14);
    printf("3. NAMES");gotoxy(10,15);
    printf("4. DATE PUBLISHED");gotoxy(10,16);
    printf("5. IDENTITY NUMBER");gotoxy(10,17);
    printf("6. HALL");gotoxy(10,18);
    printf("7. NUMBER OF BOOKS");gotoxy(10,19);
    printf("8. CANCEL");gotoxy(10,21);
    printf("Please input your choice :");
    switch(getch())
      {
       case '1':
	 {
	  clrscr();
	 //search for book by all parameters
	  intowin(10,10,30,3,"BOOKS",sbooks,20);
	  fflush(stdin);
	  intowin(10,10,30,3,"GIVE NAME",sname,20);
	  fflush(stdin);
	  intowin(10,10,30,3,"GIVE SURNAME",ssurname,20);
	  fflush(stdin);
	  intowin(10,10,30,3,"DATE PUBLISHED",sdate_pub,20);
	  fflush(stdin);
	  clrscr();
	  gotoxy(15,5);
	  printf(" IDENTITY NUMBER=");
	  fflush(stdin);
	  sbooknum=testnumber(num,0,9999);
	  fflush(stdin);
	  clrscr();
	  gotoxy(15,5);
	  printf("      HALL NUMBER=");
	  fflush(stdin);
	  shall=testnumber(num,0,5)-1;
	  clrscr();
	  gotoxy(15,5);
	  printf("  NUMBER OF BOOKS=");
	  fflush(stdin);
	  sbooknum=testnumber(num,0,9999);
	  clrscr();
	  srch=0;
	  first=fur=info=NULL;
	  for(i=0;i<n;i++)
	     {
	     if((strcmp(scol->books,sbooks)==0)&&(strcmp(scol->firstname,sname)==0)&&(strcmp(scol->surname,ssurname)==0)&&(strcmp(scol->date_pub,sdate_pub)==0)
	     &&(scol->booknum==sbooknum)&&(scol->hall==shall))
	       {
	       if(first==NULL)
		 {
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=NULL;
		 info->forward=NULL;
		 first=info;
		 }
	       else
		 {
		 fur=info;
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=fur;
		 info->forward=NULL;
		 fur->forward=info;
		 }

	       }
	     scol=scol->forward;
	     }
	  info=first;
	  scol=info;

	  break;


	 };
       case '2':
	 {
	  clrscr();
	   //searching for those with a given title
	  intowin(10,10,30,3,"GIVE BOOK'S TITLE",sbooks,20);
	  fflush(stdin);
	  srch=0;
	  first=fur=info=NULL;
	  for(i=0;i<n;i++)
	     {
	     if(strcmp(scol->books,sbooks)==0)
	       {
	       if(first==NULL)
		 {
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=NULL;
		 info->forward=NULL;
		 first=info;
		 }
	       else
		 {
		 fur=info;
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=fur;
		 info->forward=NULL;
		 fur->forward=info;
		 }

	       }
	     scol=scol->forward;
	     }
	  info=first;
	  scol=info;

	  break;


	 };
       case '3':
	 {
	  clrscr();
	  //search by names
	  intowin(10,10,30,3,"GIVE NAME",sname,20);
	  fflush(stdin);
	  intowin(10,10,30,3,"GIVE SURNAME",ssurname,20);
	  fflush(stdin);
	  srch=0;
	  first=fur=info=NULL;
	  for(i=0;i<n;i++)
	     {
	     if((strcmp(scol->firstname,sname)==0)&&(strcmp(scol->surname,ssurname)==0))
	       {
	       if(first==NULL)
		 {
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=NULL;
		 info->forward=NULL;
		 first=info;
		 }
	       else
		 {
		 fur=info;
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=fur;
		 info->forward=NULL;
		 fur->forward=info;
		 }

	       }
	     scol=scol->forward;
	     }
	  info=first;
	  scol=info;

	  break;


	 };
       case '4':
	 {
	  clrscr();
	  //searching for those with the same date being published
	  intowin(10,10,30,3,"DATE PUBLISHED",sdate_pub,20);
	  fflush(stdin);
	  srch=0;
	  first=fur=info=NULL;
	  for(i=0;i<n;i++)
	     {
	     if(strcmp(scol->date_pub,sdate_pub)==0)
	       {
	       if(first==NULL)
		 {
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=NULL;
		 info->forward=NULL;
		 first=info;
		 }
	       else
		 {
		 fur=info;
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=fur;
		 info->forward=NULL;
		 fur->forward=info;
		 }

	       }
	     scol=scol->forward;
	     }
	  info=first;
	  scol=info;

	  break;


	 };
       case '5':
	 {
	  clrscr();
	  // search for those with same book's identity number
	  gotoxy(20,5);
	  printf(" PLEASE GIVE BOOK'S IDENTITY NUMBER ");
	  gotoxy(20,7);
	  printf(" BOOK'S IDENTITY NUMBER= ");
	  sbooknum=testnumber(num,0,9999);
	  fflush(stdin);
	  srch=0;
	  first=fur=info=NULL;
	  for(i=0;i<n;i++)
	     {
	     if((scol->booknum)==sbooknum)
	       {
	       if(first==NULL)
		 {
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=NULL;
		 info->forward=NULL;
		 first=info;
		 }
	       else
		 {
		 fur=info;
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=fur;
		 info->forward=NULL;
		 fur->forward=info;
		 }

	       }
	     scol=scol->forward;
	     }
	  info=first;
	  scol=info;

	  break;

	 };
       case '6':
	 {
	  clrscr();
	  // search with those with same hallnumber
	  gotoxy(17,6);
	  printf(" PLEASE GIVE THE HALL NUMBER TO WHICH BOOK BELONGS ");
	  gotoxy(15,5);
	  printf("{ [1]-Science , [2]-Literature , [3]-History , [4]-Law } ");
	  gotoxy(20,8);
	  printf(" HALL NUMBER= ");
	  shall=testnumber(num,0,5)-1;
	  fflush(stdin);
	  srch=0;
	  first=fur=info=NULL;
	  for(i=0;i<n;i++)
	     {
	     if((scol->hall)==shall)
	       {
	       if(first==NULL)
		 {
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=NULL;
		 info->forward=NULL;
		 first=info;
		 }
	       else
		 {
		 fur=info;
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=fur;
		 info->forward=NULL;
		 fur->forward=info;
		 }

	       }
	     scol=scol->forward;
	     }
	  info=first;
	  scol=info;

	  break;

	 };
       case '7':
	 {clrscr();        // search with same copies of books
	  gotoxy(20,5);
	  printf(" GIVE NUMBER OF COPIES OF PARTICULAR BOOK ");
	  gotoxy(20,7);
	  printf(" NUMBER OF COPIES= ");
	  snum_books=testnumber(num,0,9999);
	  fflush(stdin);
	  srch=0;
	  first=fur=info=NULL;
	  for(i=0;i<n;i++)
	     {
	     if((scol->num_books)==snum_books)
	       {
	       if(first==NULL)
		 {
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=NULL;
		 info->forward=NULL;
		 first=info;
		 }
	       else
		 {
		 fur=info;
		 info=(DATA*)malloc(sizeof(DATA));
		 info=copyelsearch(scol);
		 info->backward=fur;
		 info->forward=NULL;
		 fur->forward=info;
		 }

	       }
	     scol=scol->forward;
	     }
	  info=first;
	  scol=info;

	  break;
	 };
       case '8':
	 {
      //cancels search

	  break;
	 };
       default:
	 {
	  // default case cancels search

	  break;
	 };
      }
   textcolor(WHITE);
   return(scol);
  }
 }


//function just to copy elements
DATA *copyelsearch(DATA *scol)
{
  strcpy(info->books,scol->books);
  strcpy(info->firstname,scol->firstname);
  strcpy(info->surname,scol->surname);
  strcpy(info->date_pub,scol->date_pub);
  info->booknum=scol->booknum;
  info->hall=scol->hall;
  info->num_books=scol->num_books;
return(info);
}