Linked List Need Help Urgent

**ykchua** · 08-17-2004

Need urgent HELP for the coding below. Wonder why all records added cannot be displayed, after entering the record when trying to list them out, the list still appeared to be EMPTY.

Code:

#include<stdio.h>
#include<conio.h>
#include<malloc.h>


struct album
{
	int rec;
	int AlbumNo;
	char AlbumName[50];
    char ArtistName[50];
    int Year;
	int TotalTrack;
	char TrackName[50][50], TrackDuration[50][50];
    int trackTimeM[60];
	int trackTimeS[60];
    struct album *next;
};

typedef struct album node;

void AddAlbum();
void AddAlbum2(node *p);
void ListAlbum();
void ListAlbum2(node *p);
void ModifyAlbum();
void ModifyAlbum2(node *p);
void RemoveAlbum();
int Compare(node *p,int);

void main()
{
	int exit=1,option=0;

	node *head;
	head = NULL;
	  do
		{
 
		printf("\n===================================\n");
		printf("\nWelcome to the Music Storage System\n");
		printf("\n===================================\n\n\n");
		printf("1-- Add New Album Record\n");
		printf("2-- Display All Album Records\n");
		printf("3-- Modify Album Records\n");
		printf("4-- Remove Existing Album Records\n");
		printf("5-- Exit\n\n");
		printf("Please select your option\n\n");

			scanf("%d",&option);
			switch(option)
				{
				  case 1 :AddAlbum();
				  case 2 :ListAlbum();
				  case 3 :ModifyAlbum();
				  case 4 :RemoveAlbum();
				  case 5 :
					  {
						 exit=0;
						 break;								  				 
					  }
				  default :
					  {
						printf("\n\aPlease enter option between 1 - 5.\n");
						break;
						main();
					  }
				}

		}while(exit==1);

	getch();
}


void AddAlbum()
{
	int artist;
	node *head;
	head = NULL;
					do 
						{
							printf("\nEnter the Type of Album:\n");
							printf("1-- Single Artist\n");
							printf("2-- Multiple Artists\n\n");
							scanf("\n%d",&artist); fflush(stdin);
							switch (artist)
									{
								case 1: { 

							  if(head==NULL)
								{
									head=(node *)malloc(sizeof (node));
									AddAlbum2(head);
									head->next=NULL;
								}
							  else
								{
									node *temp;
									temp=head;
									while(temp->next!=NULL)
										{
										   temp=temp->next;
										}
									temp->next=(node *)malloc(sizeof (node));
									AddAlbum2(temp->next);
									temp->next->next=NULL;

								}
									break;	}
									
								case 2: printf("\n\aThis system only supports albums created for single artists.\n");AddAlbum();
									}
						}while (artist !=2);		


		}

void AddAlbum2(node *p)
{
	static int  rec = 0;

	p->AlbumNo = ++ rec;
	


	printf("\n\nEnter album's name : \t");
	gets(p->AlbumName);fflush(stdin);

	printf("Enter artist's name : \t");
	gets(p->ArtistName);fflush(stdin);
	
	printf("Enter album's released year : \t");
	scanf("%d",&p->Year);fflush(stdin);
	

	while (p->Year <1900 || p->Year > 2004) 
		{
	printf("Enter album's released year : ");
	scanf("%d",&p->Year);fflush(stdin);
		}

	while ( p->TotalTrack < 1 || p->TotalTrack > 20)
		{
	printf("Enter total number of tracks in the album : \t");
	scanf("%d",&p->TotalTrack);fflush(stdin);
		}	
		
	for ( int x=0; x<p->TotalTrack; x++ ) 
		{
			printf("Enter track title : \t");
			gets(p->TrackName[x]);fflush(stdin);

			printf("Enter track duration (mm:ss): \t");
			gets(p->TrackDuration[x]);fflush(stdin);

	    }
		
	main();
}

void ListAlbum()
{

	int list=0;
	node *head,*temp;
	head = NULL;

					
					    list = 0;
						 temp=head;
						 
						 while(temp != NULL)
							{
							   list = 1;
							   ListAlbum2(temp);
							   temp=temp->next;
							}

				         if (list == 0)
							{printf("\n\aThere is no record existing record.\n");}

						 main();
					  

}

void ListAlbum2(node *p)
{
	int x;
	printf("\nRecord Number: \t%d ",p->AlbumNo);
	printf("\nAlbum Name: \t%s ",p->AlbumName);
	printf("\nArtist Name: \t%s ",p->ArtistName);
	printf("\nTotal %d tracks recorded in year %d.",p->TotalTrack, p->Year);

	for (x=0;x<p->TotalTrack;x++)
		{
			printf( "\nTrack %d : %s \t\tDuration: %s\n\n", x+1, &p->TrackName[x], p->TrackDuration[x]);
		}

}


void ModifyAlbum()
{
	int num,modify=0;

	node *head,*temp;
	head = NULL;
						 modify = 0;
						 temp=head;
						 printf("\nPlease enter the record number: ");
						 scanf("%d",&num);fflush(stdin);
						 
						 while(temp != NULL)
							{
							  if(Compare(temp,num))
									{
									    modify = 1;
										ModifyAlbum2(temp);
									}
							  temp=temp->next;
							}

						 if (modify == 0)
							{printf("\n\aThere is no record existing record.\n");}
						 main();
						    		 
					  }


void ModifyAlbum2(node *p)
{
	int x,add,edit,option;

	printf("\n1-- Edit album's name");
	printf("\n2-- Edit artist's name");
	printf("\n3-- Edit album released year");
	printf("\n4-- Add additional track/s to album");


	printf("\n\nPlease select your option : ");
	scanf("%s",&option);fflush(stdin);

	switch (option)
	{
		case 1 :
			{	
				printf("\nEnter album's name : \t");
				gets(p->AlbumName);fflush(stdin);
				printf("\nAlbum's name changed.");
				break;
			}
				
		case 2 :
			{
				printf("\nEnter artist's name : \t");
				gets(p->ArtistName);fflush(stdin);
				printf("\nArtist's name changed");
				break;
			}

		case 3 :
			{	
				while (p->Year <1900 || p->Year > 2004) 
				{
				printf("Enter album's released year : \t");
				scanf("%d",&p->Year);fflush(stdin);
				}
				printf("\nAlbum's released year changed.");
				break;
			}
		
		case 4 :
			{

				while ( (p->TotalTrack + add) < 18)
					{
						printf("Enter the total number of ADDITIONAL track/s : \t");
						scanf("%d",&add);fflush(stdin);
					}	
				
				p->TotalTrack = p->TotalTrack + add;

				for ( x=1 ; x<=add; x++ ) 
					{
					
						printf("\nEnter track title : \t");
						gets(p->TrackName[p->TotalTrack+x]);fflush(stdin);
						printf("Enter track duration (mm:ss): \t\n");
						gets(p->TrackDuration[p->TotalTrack+x]);fflush(stdin);
							
					}
				printf("\nThe addtional tracks is/are successfully added.");
				break;
			}

		default : 
			{
				printf("\n\aPlease enter option between 1 - 5.\n");
				break;
			}


	}
}

void RemoveAlbum()
					  {

	int num,remove=0;

	node *head,*temp,*current,*previous;
	head = NULL;

						 remove = 0;
						 temp=head;
							printf("\nPlease enter the record number : ");
							scanf("%d",&num);fflush(stdin);

							if(Compare(head,num))
								{
									remove=1;
									temp=head;
									head=head->next;
									free(temp);
								}
							else
								{
									previous=head;
									current = head->next;
									
									while (current !=NULL && current->AlbumNo != num)
										{
											previous = current;
											current = current->next;
										}

									if (current != NULL)
										{
											remove=1;
											temp = current;
											previous->next = current->next;
											free(temp);
										}
								}

							
							 if (remove == 0)
								{printf("\n\aThere is no existing record.");}
							 else
								{printf("\n\aRecord removed.");}
												
					        main();	
						    								 			
					  }


int Compare(node *p,int got)
{
	if(p->AlbumNo==got)
		{return 1;}
	else
		{return 0;}

}

**bigtamscot** · 08-17-2004

Your problem maybe here...

Code:

void ListAlbum()
{
         int list=0;
         node *head,*temp;

         head = NULL;  //you set head to NULL
         list = 0;  // list is already been initialised
         temp=head;    // you then set temp to NULL

         // temp equals NULL so the condition is met,
         // loop is never processed
         while(temp != NULL)
         {
                     list = 1;
                     ListAlbum2(temp);
                      temp=temp->next;
          }

           // list equals 0 so message is shown
           if (list == 0)
           {
                     printf("\n\aThere is no record existing record.\n");
            }

           // donot call main BAD, just end function normally 
           // nothing required
           main();
}

**moi** · 08-17-2004

Please don't say "urgent". While your problem may be urgent to you, it's not to us; only your fault if you have a project due tomorrow.

Try to keep your code as standard as possible, so those trying to aid you can compile your code. Writing in compliance with standards is also good coding form. In here, this inculdes removing the <conio.h> and getch(). maybe fix those tab stops too

Don't use gets(), it's unsafe http://faq.cprogramming.com/cgi-bin/...&id=1043284351
When using scanf(), check for failure, more about this here
http://faq.cprogramming.com/cgi-bin/...&id=1043284392
fflush(stdin) is also nonstandard
http://faq.cprogramming.com/cgi-bin/...&id=1043284351
Always check to make sure malloc () didn't fail.
void main() is incorrect
http://faq.cprogramming.com/cgi-bin/...&id=1043284376

**Salem** · 08-17-2004

Did I mention formatting in another thread?
Probably.
This is just as bad.

**Salem** · 08-17-2004

The OP's code - reformatted (thanks to indent -kr -ts4 -nut hello.c)

Code:

#include<stdio.h>
#include<conio.h>
#include<malloc.h>


struct album {
    int rec;
    int AlbumNo;
    char AlbumName[50];
    char ArtistName[50];
    int Year;
    int TotalTrack;
    char TrackName[50][50], TrackDuration[50][50];
    int trackTimeM[60];
    int trackTimeS[60];
    struct album *next;
};

typedef struct album node;

void AddAlbum();
void AddAlbum2(node * p);
void ListAlbum();
void ListAlbum2(node * p);
void ModifyAlbum();
void ModifyAlbum2(node * p);
void RemoveAlbum();
int Compare(node * p, int);

void main()
{
    int exit = 1, option = 0;

    node *head;
    head = NULL;
    do {

        printf("\n===================================\n");
        printf("\nWelcome to the Music Storage System\n");
        printf("\n===================================\n\n\n");
        printf("1-- Add New Album Record\n");
        printf("2-- Display All Album Records\n");
        printf("3-- Modify Album Records\n");
        printf("4-- Remove Existing Album Records\n");
        printf("5-- Exit\n\n");
        printf("Please select your option\n\n");

        scanf("%d", &option);
        switch (option) {
        case 1:
            AddAlbum();
        case 2:
            ListAlbum();
        case 3:
            ModifyAlbum();
        case 4:
            RemoveAlbum();
        case 5:
            {
                exit = 0;
                break;
            }
        default:
            {
                printf("\n\aPlease enter option between 1 - 5.\n");
                break;
                main();
            }
        }

    } while (exit == 1);

    getch();
}


void AddAlbum()
{
    int artist;
    node *head;
    head = NULL;
    do {
        printf("\nEnter the Type of Album:\n");
        printf("1-- Single Artist\n");
        printf("2-- Multiple Artists\n\n");
        scanf("\n%d", &artist);
        fflush(stdin);
        switch (artist) {
        case 1:{

                if (head == NULL) {
                    head = (node *) malloc(sizeof(node));
                    AddAlbum2(head);
                    head->next = NULL;
                } else {
                    node *temp;
                    temp = head;
                    while (temp->next != NULL) {
                        temp = temp->next;
                    }
                    temp->next = (node *) malloc(sizeof(node));
                    AddAlbum2(temp->next);
                    temp->next->next = NULL;

                }
                break;
            }

        case 2:
            printf
                ("\n\aThis system only supports albums created for single artists.\n");
            AddAlbum();
        }
    } while (artist != 2);


}

void AddAlbum2(node * p)
{
    static int rec = 0;

    p->AlbumNo = ++rec;



    printf("\n\nEnter album's name : \t");
    gets(p->AlbumName);
    fflush(stdin);

    printf("Enter artist's name : \t");
    gets(p->ArtistName);
    fflush(stdin);

    printf("Enter album's released year : \t");
    scanf("%d", &p->Year);
    fflush(stdin);


    while (p->Year < 1900 || p->Year > 2004) {
        printf("Enter album's released year : ");
        scanf("%d", &p->Year);
        fflush(stdin);
    }

    while (p->TotalTrack < 1 || p->TotalTrack > 20) {
        printf("Enter total number of tracks in the album : \t");
        scanf("%d", &p->TotalTrack);
        fflush(stdin);
    }

    for (int x = 0; x < p->TotalTrack; x++) {
        printf("Enter track title : \t");
        gets(p->TrackName[x]);
        fflush(stdin);

        printf("Enter track duration (mm:ss): \t");
        gets(p->TrackDuration[x]);
        fflush(stdin);

    }

    main();
}

void ListAlbum()
{

    int list = 0;
    node *head, *temp;
    head = NULL;


    list = 0;
    temp = head;

    while (temp != NULL) {
        list = 1;
        ListAlbum2(temp);
        temp = temp->next;
    }

    if (list == 0) {
        printf("\n\aThere is no record existing record.\n");
    }

    main();


}

void ListAlbum2(node * p)
{
    int x;
    printf("\nRecord Number: \t%d ", p->AlbumNo);
    printf("\nAlbum Name: \t%s ", p->AlbumName);
    printf("\nArtist Name: \t%s ", p->ArtistName);
    printf("\nTotal %d tracks recorded in year %d.", p->TotalTrack,
           p->Year);

    for (x = 0; x < p->TotalTrack; x++) {
        printf("\nTrack %d : %s \t\tDuration: %s\n\n", x + 1,
               &p->TrackName[x], p->TrackDuration[x]);
    }

}


void ModifyAlbum()
{
    int num, modify = 0;

    node *head, *temp;
    head = NULL;
    modify = 0;
    temp = head;
    printf("\nPlease enter the record number: ");
    scanf("%d", &num);
    fflush(stdin);

    while (temp != NULL) {
        if (Compare(temp, num)) {
            modify = 1;
            ModifyAlbum2(temp);
        }
        temp = temp->next;
    }

    if (modify == 0) {
        printf("\n\aThere is no record existing record.\n");
    }
    main();

}


void ModifyAlbum2(node * p)
{
    int x, add, edit, option;

    printf("\n1-- Edit album's name");
    printf("\n2-- Edit artist's name");
    printf("\n3-- Edit album released year");
    printf("\n4-- Add additional track/s to album");


    printf("\n\nPlease select your option : ");
    scanf("%s", &option);
    fflush(stdin);

    switch (option) {
    case 1:
        {
            printf("\nEnter album's name : \t");
            gets(p->AlbumName);
            fflush(stdin);
            printf("\nAlbum's name changed.");
            break;
        }

    case 2:
        {
            printf("\nEnter artist's name : \t");
            gets(p->ArtistName);
            fflush(stdin);
            printf("\nArtist's name changed");
            break;
        }

    case 3:
        {
            while (p->Year < 1900 || p->Year > 2004) {
                printf("Enter album's released year : \t");
                scanf("%d", &p->Year);
                fflush(stdin);
            }
            printf("\nAlbum's released year changed.");
            break;
        }

    case 4:
        {

            while ((p->TotalTrack + add) < 18) {
                printf
                    ("Enter the total number of ADDITIONAL track/s : \t");
                scanf("%d", &add);
                fflush(stdin);
            }

            p->TotalTrack = p->TotalTrack + add;

            for (x = 1; x <= add; x++) {

                printf("\nEnter track title : \t");
                gets(p->TrackName[p->TotalTrack + x]);
                fflush(stdin);
                printf("Enter track duration (mm:ss): \t\n");
                gets(p->TrackDuration[p->TotalTrack + x]);
                fflush(stdin);

            }
            printf("\nThe addtional tracks is/are successfully added.");
            break;
        }

    default:
        {
            printf("\n\aPlease enter option between 1 - 5.\n");
            break;
        }


    }
}

void RemoveAlbum()
{

    int num, remove = 0;

    node *head, *temp, *current, *previous;
    head = NULL;

    remove = 0;
    temp = head;
    printf("\nPlease enter the record number : ");
    scanf("%d", &num);
    fflush(stdin);

    if (Compare(head, num)) {
        remove = 1;
        temp = head;
        head = head->next;
        free(temp);
    } else {
        previous = head;
        current = head->next;

        while (current != NULL && current->AlbumNo != num) {
            previous = current;
            current = current->next;
        }

        if (current != NULL) {
            remove = 1;
            temp = current;
            previous->next = current->next;
            free(temp);
        }
    }


    if (remove == 0) {
        printf("\n\aThere is no existing record.");
    } else {
        printf("\n\aRecord removed.");
    }

    main();

}


int Compare(node * p, int got)
{
    if (p->AlbumNo == got) {
        return 1;
    } else {
        return 0;
    }

}

TIP for beginners.
DO NOT use TAB characters for formatting code. Every single editor / printer / web browser / whatever will treat them differently, so its a guarantee that it will look a mess somewhere.
So please figure out how to make your editor "use spaces for tabs".

**manofsteel972** · 08-17-2004

Maybe they could solve the problem on the server end by filtering what is bewtween code tags and automatigically format for the post? If not at least it would be a cool project for some body to work on.

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