title: how to initialize a variable to the type "double" in ruby
body: <p>like in C and C++</p>
  
  <pre><code>double x
  </code></pre>
  
  <p>How to do it in ruby ?</p>
  
  <p>Or to be in the type float?</p>
  
  <p>I want to run </p>
  
  <pre><code>x=5/2
  </code></pre>
  
  <p>then </p>
  
  <pre><code>x=2.5
  </code></pre>
  
  <p>instead of </p>
  
  <pre><code>x=2
  </code></pre>