title: How to define a function does not return or return void in scala
body: <p>With more and more confused raised up, I even find that I can not understand simple Function definition in Scala:</p>
  
  <p>If I just want to define a function doing nothing but some unuseful addition, how can I do that like this:</p>
  
  <pre><code>def nothing(a:Int, b:Int) = {
      a = a+1; b=b+1;
  }
  </code></pre>
  
  <p><strong>What I want is add 1 to a and b and return nothing or void.</strong></p>
  
  <p>I kinda feel the more I learnt, the more I begin unfamiliar with, even to those I learnt before, this is terrible.</p>