title: Calculate Last Day of the Next Month
body: <p>I am attempting to use the DateTime function in C# to calculate the last day of next month.</p>
  
  <p>For example, today is December 17th 2015.  I want the DateTime function to return January 31st 2016 (the last day of next month).</p>
  
  <p>I am using the following to calculate the first day of next month (this works):</p>
  
  <pre><code>DateTime firstDayNextMonth = DateTime.Today.AddDays(-DateTime.Now.Day+1).AddMonths(1);
  </code></pre>