title: std::unordered_map and duplicate keys
body: <p>I'm using an stl unordered_map, and I can't seem to get the count method to work.
  This is my program:</p>
  
  <pre><code>typedef unordered_map&lt;char, int&gt; Mymap;
  int main() 
  {
      Mymap m;  
  
      m.insert(Mymap::value_type('a', 1)); 
      m.insert(Mymap::value_type('b', 2)); 
      m.insert(Mymap::value_type('c', 3)); 
      m.insert(Mymap::value_type('b', 4)); 
      m.insert(Mymap::value_type('b', 5)); 
  
      cout &lt;&lt; m.count('b') &lt;&lt; endl;
  
      return 0; 
  } 
  </code></pre>
  
  <p>The documentation for unordered_map says that <code>unordered_map::count(const Key&amp; k)</code> returns the number of elements with the key <code>k</code>.
  So I would expect the output here to be <code>3</code>, whereas the real output is <code>1</code>. Why?</p>