title: C++14 Variable Templates
body: <p>I came to know about C++14 comes with <em>variable template</em>.  </p>
  
  <pre><code> template&lt;typename T&gt;
      constexpr T pi = T(3.1415926535897932385);
  </code></pre>
  
  <p>My question is - When we use variable templates over normal variable? Please Give me some example.</p>