title: prefix attribute must be followed by an interface or protocol stack overflow
body: <p>[Compiler error] prefix attribute must be followed by an interface or protocol stack overflow
  Code worked fine in prev. project. I feel like an idiot for posting such a simple question. whats wrong with this stuff?</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  #import "FlipsideViewController.h"
  
  @interface MainViewController : UIViewController &lt;FlipsideViewControllerDelegate&gt;
  &lt;UIPickerViewDelegate&gt;&lt;UIPickerViewDataSource&gt;
  
  @property (strong, nonatomic) IBOutlet UITextField *inputText;
  @property(strong, nonatomic) IBOutlet UIPickerView *picker;
  @property(strong, nonatomic) IBOutlet UILabel *resultLabel;
  @property(strong, nonatomic) NSArray *_convertFrom;
  @property(strong, nonatomic) NSArray *_convertTo;
  @property(strong, nonatomic) NSArray *_convertRates;
  @property(strong, nonatomic) IBOutlet UILabel *formelLabel;
  @property(strong, nonatomic) IBOutlet UITextField *inputText;
  
  
  -(IBAction)textFieldReturn:(id)sender;
  -(IBAction)backgroundTouched:(id)sender;
  
  
  @end
  </code></pre>