title: Dealing with accuracy problems in floating-point numbers
body: <p>I was wondering if there is a way of overcoming an accuracy problem that seems to be the result of my machine's internal representation of floating-point numbers:</p>
  
  <p>For the sake of clarity the problem is summarized as:</p>
  
  <pre><code>// str is "4.600";   atof( str ) is 4.5999999999999996  
  double mw = atof( str )  
  
  // The variables used in the columns calculation below are:   
  //  
  //                    mw = 4.5999999999999996  
  //                    p = 0.2  
  //                    g = 0.2  
  //                    h = 1 (integer)  
  
  int columns = (int) ( ( mw - ( h * 11 * p ) ) / ( ( h * 11 * p ) + g ) ) + 1;
  </code></pre>
  
  <p>Prior to casting to an integer type the result of the columns calculation is 1.9999999999999996; so near yet so far from the desired result of 2.0.</p>
  
  <p>Any suggestions most welcome.</p>