title: How can I go decrement the iterator of a std::map by a certain number?
body: <p>With an std::vector I can do:</p>
  
  <pre><code>std::vector&lt;int&gt; h;
  auto it = h.end() - 2;
  </code></pre>
  
  <p>But with the std::map I can't do:</p>
  
  <pre><code>std::map&lt;int, int&gt; h;
  auto it = h.end() - 2;
  </code></pre>
  
  <p>I can only do:</p>
  
  <pre><code>auto it = --h.end();
  </code></pre>
  
  <p>This is for example if I want the member two from the end, or three from the end, or whatever.</p>