title: Simple C number formatting
body: <p>This a very simple c question. </p>
  
  <p>Is there a way to format a float for printf so that it has xx SIGNIFICANT decimals?</p>
  
  <p>So I'm not talking about, say, <code>%5.3f</code> float, but if I had</p>
  
  <pre><code>float x=0.00001899383
  </code></pre>
  
  <p>How would I output 0.0000189 if I wanted <em>up to</em> the first three non-zero decimals?</p>