title: Returning the greatest key strictly less than the given key in a C++ Map
body: <p>Is there a way the C++ STL Maps support this, since lower_bound and upper_bound on maps strictly return the value greater than the passed value.</p>
  
  <p><a href="http://java.sun.com/javase/6/docs/api/java/util/NavigableMap.html#lowerKey(K)" rel="noreferrer">Lower key </a></p>
  
  <p>Use case I have a map with times as keys in a sorted manner so in a MAP</p>
  
  <pre><code>time t1   = value1
  time t2   = value2
  time t2.5 = value3
  </code></pre>
  
  <p>In this case if I pass to this MAP t2.3 then it should give me value2. Does doing a lower_bound on the map and going back one element equivalent to the  "returning greatest key strictly less than given key" i.e</p>
  
  <pre><code>iterator = map.upper_bound(2.3)
  and then 
  iterator--;
  </code></pre>