title: Library for the Basic Data Structures, such as Queue, in C
body: <p><strong>Problem:</strong> to find the right data structure for the queue:</p>
  
  <pre><code> #include &lt;stdio.h&gt;                                                                                                                                                             
   #include &lt;stdlib.h&gt;
   #include &lt;stdarg.h&gt;
   #include &lt;time.h&gt;
  
   int main(int argc, const char *argv[])
   {
       Queue q;
       ch ='A';
       for (int k = 0; int k &lt; 4; int k++) {
           q.addQ(ch);
           ch++;
           q.addQ(ch);
           ch=q.front();
           q.removeQ();
       }
       return 0;
   }
  </code></pre>
  
  <p>I tried to compile it, but the Queue is undeclared:</p>
  
  <pre><code>$ gcc -o Qu_1 -g q_queue.c
  q_queue.c: In function 'main':
  q_queue.c:8: error: 'Queue' undeclared (first use in this function)
  </code></pre>
  
  <p><strong>Question:</strong> What is the library for the basic data structures such as the queue in the example?</p>