title: C++ string declaration
body: <p>I am learning C++ from the beginning and I don't get the whole strings topic.</p>
  
  <p>What is the difference between the following three codes?</p>
  
  <ol>
  <li><code>std::string s = std::string("foo");</code>  </li>
  <li><code>std::string s = new std::string("foo");</code>  </li>
  <li><code>std::string s = "foo";</code></li>
  </ol>