Simple Linked List - Not able to access nodes

问题

I'm trying to construct a simple Linked List but I get a compile error telling me the Linked List node I'm trying to access doesn't contain the field I expect it to. These are my Linked List methods:

typedef struct TinCan
    {
    int label;
    } TinCan;

typedef struct LinkedListNode
    {
    TinCan *data;
    struct LinkedListNode *next;
    } LinkedListNode;

typedef struct LinkedList
    {
    LinkedListNode *head;
    } LinkedList;

LinkedList* createList() /*creates empty linked list*/
    {
    LinkedList* myList;
    myList = (LinkedList*)malloc(sizeof(LinkedList));
    myList->head = NULL;
    }

I malloc a struct and send it to the list like so:

LinkedList* canQueue=createList();
TinCan* testCan = (TinCan*) malloc(sizeof(TinCan));
testProc->pid=69;
insertLast(canQueue, testCan);

void insertLast(LinkedList* list, ProcessActivity *newData)
    {
        int ii = 1;
    LinkedListNode* newNode = (LinkedListNode*)malloc(sizeof(LinkedListNode));
    newNode->data = newData;

    //check if queue empty
    if(list->head == NULL)
        {
        list->head = newNode;
        newNode->next=NULL;
        }
    else
        {
        LinkedListNode* current = list->head;
        while (current->next != NULL)
            {
            current = current->next;
            }
        current->next = newNode;
        printf("%d", ii);
        ii++;
        }
}

And then I try to acess the node like so:

testLinkedList(cpuQueue);

void testLinkedList(LinkedList* list)
    {
        int count = 1;
        LinkedListNode* current = list->head;
        while (current != NULL)
            {
            printf("%d: Label is is %d", count, current->data->label);



            current = current->next;
            count++;
            }
    }

The compile error shows up for the last method: 'LinkedListNode' has no member named 'label'. I can't see where I've gone wrong, can someone identify a problem with the code?

回答1:

TinCan doesn't have field pid

Maybe:

testProc->label=69;

instead of

testProc->pid=69;

回答2:

LinkedList* createList() /*creates empty linked list*/
{
  LinkedList* myList;
  myList = (LinkedList*)malloc(sizeof(LinkedList));
  myList->head = NULL;

--> return myList;

来源：https://stackoverflow.com/questions/16331530/simple-linked-list-not-able-to-access-nodes

标签

data-structures

linked-list