title: Return std::string as const reference
body: <p>I have a doubt on returning std::string as const reference.</p>
  
  <pre><code>class sample
  {
  public:
    std::string mString;
    void Set(const std::string&amp; s)
    {
      mString = s;
    }
    std::string Get()
    {
      return mString;
    }
   };
  </code></pre>
  
  <p>In the Set function I am passing the std::string as const reference, const because its value is not changing inside the function.</p>
  
  <p>And In Get function, actually I am confused here. Return std::string as value makes more sense. But I am not sure that, by  passing the string as const reference makes any advantages. By returing string as reference will increase the exectuion speed, I think So, but I am not sure. But returning it as 'const makes any benefit for this?</p>