Question

I have this popFront function for a linked list:

Node* popFront(Node* list)
{
    Node* returnMe = (Node*)malloc(sizeof(Node));
    Node* oldHead = list;

    returnMe->mData = list->mData;

    if (list->mNext != NULL)
        list = list->mNext;  // This line is definitely called
    else
        list = blankNode;    // And not this one

    free(oldHead);

    return returnMe;
}

But whenever I call it like this:

Node* list = buildList(10);
Node* oldHead = popFront(list);

printInfo(list);

‘oldHead’ is correct but ‘list’ still has its first Node.

Answer 1

If you want the variable list to change, you need to pass it by pointer. Since the value of list is Node*, you would need to pass to have the signature of popFront be Node* popFront(Node **list).