title: different output from same function with same parameters
body: <p>I am confused with following string function</p>
  
  <p><code>echo strlen("l\n2"); //give 3 in output</code> </p>
  
  <p>where as</p>
  
  <p><code>echo strlen('l\n2'); //give 4 in output</code> </p>
  
  <p>can anybody explain why ?</p>