title: assign values to selective items using STL multimap
body: <pre><code>typedef std::pair&lt;int, bool&gt; acq_pair; //edge, channel_quality
  typedef std::pair&lt;int, acq_pair&gt; ac_pair;
  typedef std::multimap&lt;int, acq_pair&gt; ac_map;
  typedef ac_map::iterator It_acq;
  
  
  int bits = acq_map.size();
  std::cout &lt;&lt; "bits = " &lt;&lt; bits &lt;&lt; std::endl;
  
  std::vector&lt;std::vector&lt;bool&gt; &gt; c_flags (1 &lt;&lt; bits);
  
  for (i = 0; i &lt; c_flags.size(); ++i)
  {
      for (j = 0; j &lt; bits; ++j)
      {
          c_flags[i].push_back( (i &amp; (1 &lt;&lt; j)) &gt; 0);      
      }           
  }
  
  std::cout &lt;&lt; "c_flags.size() = " &lt;&lt; c_flags.size() &lt;&lt; std::endl;
  
  for(i = 0; i &lt; c_flags.size(); ++i)
  {
      for(j = 0; j &lt; bits; ++j)
      {
          std::cout &lt;&lt; c_flags[i][j] &lt;&lt; std::endl;
  
          for(It_acq itc = acq_map.begin(); itc!= acq_map.end(); ++itc)
          {
              acq_pair it1 = itc-&gt;second;
              itc-&gt;second.second = c_flags[i][j];
              std::cout &lt;&lt; itc-&gt;first &lt;&lt; " : " &lt;&lt; it1.first &lt;&lt; " : " &lt;&lt; it1.second &lt;&lt; std::endl;
          }
      }   
      std::cout &lt;&lt; "\n" &lt;&lt; std::endl;
  }
  </code></pre>
  
  <p>How can I access only one item from the multimap container at a time? I want to update only the jth value in the map, but when I iterate through the map all the bool values are changed. Is there a selective way to access the map container values?</p>