title: When I use delegate to pass value to another ViewController,I find the delegate does nothing
body: <p>When I use delegate to pass value to another <code>ViewController</code>,I find the delegate does nothing. 
  I just can delete the delegate and still I can pass the value!</p>
  
  <p>When i need to pass a value from <code>ViewControllerA</code> to <code>ViewControllerB</code>, i just did this which does work!</p>
  
  <pre><code>- (IBAction)sendToB:(id)sender {
  ViewControllerB *viewB=[[ViewControllerB alloc]initWithNibName:@"ViewControllerB" bundle:nil];
  [viewB getValue:self.textInput.text];
  [self presentViewController:viewB animated:YES completion:nil];  }
  </code></pre>
  
  <p>then in <code>ViewControllerB</code>, i do get the value.
  But this is nothing to do with delegate and i remember people all say using delegate to pass value between two <code>ViewControllers</code>. So what is the difference?Thanks!</p>