title: php program to find the my birthday where day name "Monday" for another 100 years
body: <p>I was born in 1986-04-21, which is Monday. My next birthday with day name "Monday" is 1997-04-21 and so on.</p>
  
  <p>I wrote the program to find upto 100 year to find which year my birthday comes with matching day name that is monday.</p>
  
  <p>This is the code:</p>
  
  <pre><code>&lt;?php
  date_default_timezone_set('Asia/Calcutta');
  for($year = 1986; $year &lt; 2086; $year++) {
      $timestamp = mktime(0, 0, 0, 4, 21, $year);
      if(date('l', $timestamp) == 'Monday') {
          echo date('Y-m-d, l', $timestamp) . "\n";
      }
  }
  ?&gt;
  </code></pre>
  
  <p>This is the output of the program:</p>
  
  <pre><code>1986-04-21, Monday
  1997-04-21, Monday
  2003-04-21, Monday
  2008-04-21, Monday
  2014-04-21, Monday
  2025-04-21, Monday
  2031-04-21, Monday
  2036-04-21, Monday
  </code></pre>
  
  <p>Now my problem is why PHP is not supporting before 1970 and after 2040.<br>
   So how can I get the birthday after 2040 or before 1970?</p>