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POabout implementing a multi linked list
primarykey
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5927754
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5928356
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4
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4
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CreationDate
2011-05-08T13:38:10.170
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0
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2015-08-29T09:08:28.300
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2011-05-11T14:40:50.973
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592182
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743898
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0
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1
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2
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6794
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text
Body
I am working on a project which is similar to an address book. Firstly we have a number of students in a text file. I am going to implement a multi linked list which this list have 2 head+tail pointer (head+tail pointer for name,surname). These pointers show the same list but different locations because I am adding the nodes in ascending order and use double pointers to print the list backwards. The problem is I implemented the list by adding nodes by name and surname and the operation goes successfully when I insert another one. But I realized that when I deleted a node by her/his "name" and print the list again the student doesn't exist, but when I print the list by "surname" the student does exist. Then I recognize that I was implemented two separate linked lists. I was told to implement only ONE add and remove function. But how can I add a node by its first name pointers and surname pointers together? I hope I explained my issue understandably. Here are my blocks of code. My structures: <pre><code>typedef struct node { int birth_date; int zipcode; int phone_num; char first_name[50]; char last_name[50]; char city[50]; char address[50]; char email_addr[50]; struct node* fn_next; struct node* fn_pre; struct node* ln_next; struct node* ln_pre; struct node* birdat_next; struct node* birdat_pre; } NODE; typedef struct { int fn_count; int ln_count; NODE* fn_head; NODE* ln_head; NODE* fn_tail; NODE* ln_tail; }LIST; </code></pre> The code block where I read the file line by line and call the add functions: <pre><code>while ( !feof(myfile) ) { NODE* pnew_stu; if( !(pnew_stu = (NODE*) malloc(sizeof(NODE))) ) { printf("ERROR NOT ENOUGH MEMORY!!!\n"); exit(100); } fscanf(myfile,"%s", &(pnew_stu->first_name) ); fscanf(myfile,"%s", &(pnew_stu->last_name) ); fscanf(myfile,"%s", &(pnew_stu->email_addr) ); fscanf(myfile,"%d", &(pnew_stu->phone_num) ); fscanf(myfile,"%s", &(pnew_stu->address) ); fscanf(myfile,"%s", &(pnew_stu->city) ); fscanf(myfile,"%d", &(pnew_stu->zipcode) ); add_Node(list,pnew_stu); } </code></pre> And finally my add functions: <pre><code>void add_fn_Node(LIST* list, NODE* pnew_stu) { NODE* temp = list->fn_head; if( list->fn_head == NULL ) { pnew_stu->fn_next = list->fn_head; pnew_stu->fn_pre = list->fn_head; list->fn_head = pnew_stu; list->fn_count = 1; return; } else { if ( (strcmp( pnew_stu->first_name, temp->first_name )) <= 0 ) { // Basa Ekleme Kosulu pnew_stu->fn_next = temp; pnew_stu->fn_pre = temp->fn_pre; temp->fn_pre = pnew_stu; list->fn_head = pnew_stu; list->fn_count++; return; } else { while ( temp->fn_next != NULL ) { // Ortaya Ekleme Kosulu if ( (strcmp( pnew_stu->first_name, temp->first_name ) >= 0 ) && (strcmp( pnew_stu->first_name, temp->fn_next->first_name) < 0)) { pnew_stu->fn_next = temp->fn_next; pnew_stu->fn_pre = temp; temp->fn_next->fn_pre = pnew_stu; temp->fn_next = pnew_stu; list->fn_count++; return; } temp = temp->fn_next; } if ( temp->fn_next == NULL ) { // Sona Ekleme Kosulu temp->fn_next = pnew_stu; pnew_stu->fn_pre = temp; pnew_stu->fn_next = NULL; list->fn_tail = pnew_stu; list->fn_count++; return; } } } } void add_ln_Node(LIST* list, NODE* pnew_stu) { NODE* temp = list->ln_head; if( list->ln_head == NULL ) { pnew_stu->ln_next = list->ln_head; pnew_stu->ln_pre = list->ln_head; list->ln_head = pnew_stu; list->ln_count = 1; return; } else { if ( (strcmp( pnew_stu->last_name, temp->last_name )) <= 0 ) { // Basa Ekleme Kosulu pnew_stu->ln_next = temp; pnew_stu->ln_pre = temp->ln_pre; temp->ln_pre = pnew_stu; list->ln_head = pnew_stu; list->ln_count++; return; } else { while ( temp->ln_next != NULL ) { // Ortaya Ekleme Kosulu if ( (strcmp( pnew_stu->last_name, temp->last_name ) >= 0 ) && (strcmp( pnew_stu->last_name, temp->ln_next->last_name) < 0)) { pnew_stu->ln_next = temp->ln_next; pnew_stu->ln_pre = temp; temp->ln_next->ln_pre = pnew_stu; temp->ln_next = pnew_stu; list->ln_count++; return; } temp = temp->ln_next; } if ( temp->ln_next == NULL ) { // Sona Ekleme Kosulu temp->ln_next = pnew_stu; pnew_stu->ln_pre = temp; pnew_stu->ln_next = NULL; list->ln_tail = pnew_stu; list->ln_count++; return; } } } } </code></pre> My delete functions: <pre><code>void del_fn_name(LIST* list, char* str_key) { NODE* temp; int num,counter=1,flag; temp = list->fn_head; if( list->fn_head == NULL ) { printf("The list is EMPTY!!!\n"); return; } flag = search_fn(list,str_key); if ( flag ) { printf("Enter the number of student you want to delete : "); scanf("%d", &num); if( strcmp( list->fn_head->first_name, str_key ) == 0 ) { // Bastan Silme Kosulu if( num == counter ) { list->fn_head->fn_next->fn_pre = list->fn_head; list->fn_head = list->fn_head->fn_next; free(list->fn_head); printf("%s is deleted and the new header is %s\n", str_key, list->fn_head->first_name ); return; } counter++; } temp = temp->fn_next; while ( temp->fn_next != NULL ) { if( strcmp( temp->first_name, str_key ) == 0 ) { if( num == counter ) { temp->fn_pre->fn_next = temp->fn_next; temp->fn_next->fn_pre = temp->fn_pre; free(temp); printf("%s deleted at between %s and %s\n", str_key, temp->fn_pre->first_name, temp->fn_next->first_name); return; } counter++; } temp = temp->fn_next; } if( temp->fn_next == NULL ) { // Sondan Silme Kosulu if( strcmp(temp->first_name, str_key) == 0 ) { if( num == counter ) { list->fn_tail = temp->fn_pre; temp->fn_pre->fn_next = NULL; free(temp); printf("%s deleted at the end and new tail is %s \n", str_key, list->fn_tail->first_name ); return; } } } } void del_ln_name(LIST* list, char* str_key) { NODE* temp; int num,counter=1,flag; temp = list->ln_head; if( list->ln_head == NULL ) { printf("The list is EMPTY!!!\n"); return; } flag = search_ln(list,str_key); if ( flag ) { printf("Enter the number of student you want to delete : "); scanf("%d", &num); if( strcmp( list->ln_head->last_name, str_key ) == 0 ) { // Bastan Silme Kosulu if( num == counter ) { temp->ln_next->ln_pre = list->ln_head; list->ln_head = temp->ln_next; free(temp); printf("%s is deleted and the new header is %s\n", str_key, list->ln_head->last_name ); return; } counter++; } temp = temp->ln_next; while ( temp->ln_next != NULL ) { if( strcmp( temp->last_name, str_key ) == 0 ) { if( num == counter ) { temp->ln_pre->ln_next = temp->ln_next; temp->ln_next->ln_pre = temp->ln_pre; free(temp); printf("%s deleted at between %s and %s\n", str_key, temp->ln_pre->last_name, temp->ln_next->last_name); return; } counter++; } temp = temp->ln_next; } if( temp->ln_next == NULL ) { // Sondan Silme Kosulu printf("The last item %s second last item %s\n", temp->first_name, list->fn_tail->fn_pre->first_name);*/ if( strcmp(temp->last_name, str_key) == 0 ) { if( num == counter ) { list->ln_tail = temp->ln_pre; temp->ln_pre->ln_next = NULL; free(temp); printf("%s deleted at the end and new tail is %s \n", str_key, list->ln_tail->last_name ); return; } } } } </code></pre> The integers <code>flag</code> and <code>counter</code> are for deleting the duplicate students. For example, if there are three duplicates it asks me to which number of student I want to delete. So if I enter number 2 it deletes the second duplicate.
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about implementing a multi linked list
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