Programming tricks - Sentinel

sentinel.cpp

/**
 * Sentinels: http://stackoverflow.com/a/5384593
 */

template<typename T>
decltype(auto) find_without_sentinel(const T& c)
{
  for (iterator i=c.begin(); i!=c.end(); ++i)   // first branch here
  {
    if (*i == x)    // second branch here
      return i;
  }
  return list.end();
}

template<typename T>
decltype(auto) find_using_sentinel(const T& c)
{
  iterator i=list.begin();
  *list.end() = x;

  while (*i != x)     // just this branch!
    ++i;

  return i;
}