title: How to convert an instance of std::string to lower case
body: <p>I want to convert a <code>std::string</code> to lowercase. I am aware of the function <code>tolower()</code>. However, in the past I have had issues with this function and it is hardly ideal anyway as using it with a <code>std::string</code> would require iterating over each character.</p>
  <p>Is there an alternative which works 100% of the time?</p>