title: error: request for member 'clear' in 'graph', which is of non-class type
body: <p>When I try to compile the following code:</p>
  
  <pre><code>#include &lt;cstdio&gt;
  #include &lt;vector&gt;
  #include &lt;queue&gt;
  using namespace std;
  
  #define pii pair&lt;int, int&gt;
  
  vector&lt;pii&gt; graph[100001];
  
  int main() {
      graph.clear();
      return 0;
  }
  </code></pre>
  
  <p>I get this error:</p>
  
  <pre><code>error: request for member 'clear' in 'graph', which is of non-class type 'std::vector&lt;std::pair&lt;int, int&gt; &gt; [100001]'
  </code></pre>
  
  <p>Any help is appreciated.</p>