title: What is the use of variadic constructor in C++?
body: <p>Consider following program:</p>
  
  <pre><code>#include &lt;iostream&gt;
  struct Test
  {
      Test(...)
      {
          std::cout&lt;&lt;"Variadic constructor\n";
      }
  };
  int main()
  {
      Test t;
      t={3,4,5};
  }
  </code></pre>
  
  <p>I think it is variadic constructor. Does the C++ standard says that constructor can be variadic? What is the use of such constructor? What is the rationale for allowing variadic constructor?</p>