title: How to format number adding points between each 3 numbers
body: <p>I'm unable to create a function that formate numbers like that : </p>
  
  <pre><code>1000 -&gt; 1.000
  1000000-&gt; 1.000.0000
  99999-&gt; 99.999
  </code></pre>
  
  <p>is there any function in C for that? if it doesn't exist, can you give me an idea about how to it manually?<br>
  Thank you,</p>