title: How to eliminate Perl rounding errors
body: <p>Consider the following program:</p>
  
  <pre><code>$x=12345678901.234567000;
  $y=($x-int($x))*1000000000;
  printf("%f:%f\n",$x,$y);
  </code></pre>
  
  <p>Here's what is prints:</p>
  
  <p><code>12345678901.234568:234567642.211914</code></p>
  
  <p>I was expecting:</p>
  
  <p><code>12345678901.234567:234567000</code></p>
  
  <p>This appears to be some sort of rounding issue in Perl.<br>
  How could I change it to get <code>234567000</code> instead?<br>
  Did I do something wrong?</p>