title: Checking if queue is empty
body: <p>I'm new to C and I'm trying to code a queue problem.  At the moment, I'm coding something that will check if the queue is empty.  This is what I have so far:</p>
  <p>For Queue.h (this was provided by our instructor)</p>
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;stdlib.h&gt;
  
  struct queueNode {
      char data;
      struct queueNode *nextPtr;
  };
  
  typedef struct queueNode QueueNode;
  typedef QueueNode* QueueNodePtr;
  
  typedef struct Queue {
      QueueNodePtr head;
      QueueNodePtr tail;
  } Queue;
  
  void instructions();
  int isEmpty(Queue);
  void enqueue(Queue*, char);
  char dequeue(Queue*);
  void printQueue(Queue);
  void freeQueue(Queue*);
  </code></pre>
  <p>For Queue.c</p>
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;stdlib.h&gt;
  
  #include &quot;Queue.h&quot;
  
  int isEmpty(struct Queue queue)
   {
       if (Queue == NULL)
       {
           return 1;
       }
   }
  </code></pre>
  <p>The problem is in line 8 of Queue.c, the compiler says &quot;error: expected expression before 'Queue'&quot;  How will I resolve this?</p>
  <p>Edit: I tried to use <strong>queue == NULL</strong> instead of <strong>Queue == NULL</strong> and the compiler said: error: invalid operands to binary == (have 'struct Queue' and 'void*').</p>
  <p>Thank you very much!</p>