Databases
StackOverflow2013
Postsdbo
POPointers Linked Lists C
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POPointers Linked Lists C
    primarykey
    data
    text
    <p>Did I do this right? I'm getting a strange error here... </p> <pre> linked.c: In function ‘push’: linked.c:50:19: warning: assignment from incompatible pointer type [enabled by default] linked.c: In function ‘main’: linked.c:146:9: error: incompatible type for argument 1 of ‘push’ linked.c:45:6: note: expected ‘struct node **’ but argument is of type ‘struct node’ ~/swen250/CLinkedList$ gcc -o linked linked.c linked.c: In function ‘push’: linked.c:50:19: warning: assignment from incompatible pointer type [enabled by default] ~/swen250/CLinkedList$ gcc -o linked linked.c linked.c: In function ‘pop’: linked.c:63:19: error: request for member ‘data’ in something not a structure or union linked.c:64:20: error: request for member ‘next’ in something not a structure or union linked.c: In function ‘copyList’: linked.c:106:9: warning: passing argument 1 of ‘appendNode’ from incompatible pointer type [enabled by default] linked.c:75:6: note: expected ‘struct node **’ but argument is of type ‘struct node *’ </pre> <pre><code>#include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; struct node { int data; struct node* next; }; static int length(struct node** head); static void push(struct node** head, int data); static int pop(struct node** head); static void appendNode(struct node** head, int data); static struct node *copyList(struct node** head); static void printList(struct node** head); /************************************************************ length - return length of a list ************************************************************/ int length(struct node** head) { int count = 0; struct node* current = NULL; current = *head; while (current != NULL) { current = current-&gt;next; ++count; } return count; } /************************************************************ push - add new node at beginning of list ************************************************************/ void push(struct node** head, int data) { struct node* new_ptr = NULL; new_ptr = (struct node*)malloc(sizeof(struct node)); new_ptr-&gt;data = data; new_ptr-&gt;next = *head; *head = new_ptr; } /************************************************************ pop - delete node at beginning of non-empty list and return its data ************************************************************/ int pop(struct node** head) { int val = 0; struct node* temp = NULL; if (*head != NULL) { val = head-&gt;data; temp = head-&gt;next; free(head); *head = temp; } return(val); } /************************************************************ appendNode - add new node at end of list ************************************************************/ void appendNode(struct node** head, int data) { struct node* current = NULL; struct node* previous = NULL; struct node* new_ptr = NULL; current = *head; previous = current; while (current != NULL) { previous = current; current = current-&gt;next; } new_ptr = (struct node*)malloc(sizeof(struct node)); new_ptr-&gt;data = data; new_ptr-&gt;next = NULL; previous = new_ptr; } /************************************************************ copyList - return new copy of list ************************************************************/ struct node* copyList(struct node** head) { struct node* copy = NULL; struct node* current = NULL; struct node* new_ptr = NULL; /* Copy current head to copy */ current = *head; while (current != NULL) { appendNode(copy, current-&gt;data); current = current-&gt;next; } return copy; } /************************************************************ printList - print linked list as "List: &lt; 2, 5, 6 &gt;" (example) ************************************************************/ void printList(struct node** head) { struct node* current = NULL; printf("List: &lt; "); current = *head; if (current == NULL) printf("none "); while (current != NULL) { printf("%d", current-&gt;data); current = current-&gt;next; if (current != NULL) printf(", "); } printf(" &gt;\n"); } void main() { int i; // index used for loops struct node *list_a; // a new list struct node *list_a_copy; // copy of list list_a = NULL; // initialize empty list list_a_copy = NULL; // initialize empy list // test push for (i = 0; i &lt; 4; ++i) push(&amp;list_a, i); // test length printf("Length of list = %d\n", length(&amp;list_a)); // test print head list printf("head:\n"); printList(&amp;list_a); // test append node for (i = 4; i &lt; 8; ++i) appendNode(&amp;list_a, i); // test print head list printf("head(append):\n"); printList(&amp;list_a); // make a copy of list list_a_copy = copyList(&amp;list_a); // test pop head list for (i = 0; i &lt; 4; ++i) printf("%d popped\n", pop(&amp;list_a)); // test print copy list printf("head copy:\n"); printList(&amp;list_a_copy); // test pop copy list for (i = 0; i &lt; 4; ++i) printf("%d popped\n", pop(&amp;list_a_copy)); } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USvisc
    1. USvisc
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POPointers Linked Lists C
      1. This table or related slice is empty.
      1. VTDownMod
    1. COOne of the issues that I see is, your using a double pointer in the context of a single pointer.
      singulars
      1. POPointers Linked Lists C
      1. USMike G
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload