title: retrieving integer value from the UITextField into a NSInteger variable
body: <pre><code>UITextField *textField;
  NSInteger intRollNumber;
  </code></pre>
  
  <p>I want to take <code>rollNumber</code> as input from the <code>textField</code> and store the value into <code>intRollNumber</code> .</p>
  
  <p>How i do that? Because I am unable to convert the string into integer.</p>