Why does my linked list code result in link errors?
<p>I'm new to linklist, and i'm having a tough time with it. I'm trying to display some values that i've appended to the nodes, But i keep getting linkerror messages. Here is what I have so far.</p>

<pre><code>LinkList.h
-


    #ifndef LINKLIST_H
    #define LINKLIST_H

    class LinkList
    {
    private:
        struct ListNode
        {
            int value;
            ListNode *next;
        };

        ListNode *head;

    public:
        LinkList();
        void insertNode(int);

        void deleteNode(int);
        void appendNode(int);
        void display() const;

        //~LinkList();
    };
    #endif


Impl.cpp
-

    #include &lt;iostream&gt;
    #include "LinkList.h"
    using namespace std;

    void LinkList::appendNode(int num)
    {
        ListNode * newNode;
        ListNode * nodePtr;

        newNode = new ListNode;
        newNode-&gt;value = num;
        newNode-&gt;next = NULL;

        if(!head)
        {
            head = newNode;
            head-&gt;value = num;
            head-&gt;next=NULL;
        }
        else
        {
            nodePtr = head;

            while(nodePtr-&gt;next!=NULL)
                nodePtr = nodePtr-&gt;next;
            newNode = new ListNode;
            newNode-&gt;value = num;
            newNode-&gt;next = NULL;

            nodePtr-&gt;next = newNode;
        }
    }

    void LinkList::display() const
    {
        ListNode *nodePtr;
        nodePtr = head;

        while (nodePtr != NULL)
        {
            cout &lt;&lt; nodePtr-&gt;value &lt;&lt; endl;

            nodePtr = nodePtr-&gt;next;
        }
    }
</code></pre>

<p>LinkList::LinkList()
{
    head = NULL;
}</p>

<pre><code>main.cpp
-


    #include &lt;iostream&gt;
    #include "LinkList.h"

    using namespace std;

    int main()
    {
        LinkList mine;

        mine.appendNode(6);
        mine.appendNode(9);
        mine.appendNode(11);

        mine.display();

        return 0;
    }
</code></pre>

<p>I fixed some of the initial problems but the program just crashes when it  runs and i'm not sure why</p>

<p>I'm not sure what the problems is, any help would be greatly appreciated.</p>
