title: Error on try to free memory from a Binary Tree
body: <p>I try to free the memory recursive, and when I try to display to tree, to show a message that the tree has been freed.
  The code for the delete is</p>
  
  <pre><code>void stergereArbore(ArboreBin*rad) {
      if (rad) {
          stergereArbore(rad-&gt;st);
          stergereArbore(rad-&gt;dr);
          free(rad-&gt;avion.model);
          free(rad-&gt;avion.preturi);
          free(rad);
      }
  }
  </code></pre>
  
  <p>and for display is </p>
  
  <pre><code>void afisareSRD(ArboreBin*a) {
      if (a) {
          afisareSRD(a-&gt;st);
          afisareAvion(a-&gt;avion);
          afisareSRD(a-&gt;dr);
      }
      else {
          printf("Empty");
      }
  }
  </code></pre>
  
  <p>and the error message. I`m kind of new to data structures, and maybe I misspelled something.
  <a href="https://i.stack.imgur.com/Rbnci.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Rbnci.png" alt="enter image description here"></a></p>