1#import "ViewController.h"
 2#import "Brain.h"
 3
 4@interface ViewController ()
 5@property BOOL enteringNumber;
 6@end
 7
 8@implementation ViewController
 9
10- (void)viewDidLoad
11{
12    [super viewDidLoad];
13    if (!self.myBrain)
14    {
15      self.myBrain = [[Brain alloc] init];
16    }
17	// Do any additional setup after loading the view, typically from a nib.
18}
19
20- (void)didReceiveMemoryWarning
21{
22    [super didReceiveMemoryWarning];
23    // Dispose of any resources that can be recreated.
24}
25
26-(IBAction) numberPressed:(UIButton *)sender
27{
28  NSString * number = sender.currentTitle;
29  if (self.enteringNumber)
30  {
31    self.display.text = [self.display.text stringByAppendingString:number];
32  }
33  else
34  {
35    self.display.text = number;
36    self.enteringNumber = YES;
37  }
38}
39
40-(IBAction) operationPressed:(UIButton *)sender
41{
42  if(self.enteringNumber)
43  {
44    [self enterPressed:(UIButton *)sender];
45  }
46  self.display.text = [NSString stringWithFormat:@"%g", [self.myBrain performOperation:sender.currentTitle]];
47}
48
49-(IBAction) enterPressed:(id)sender
50{
51  [self.myBrain addObject:[self.display.text doubleValue]];
52  self.enteringNumber = NO;
53}
54
55-(IBAction) clearPressed:(id)sender
56{
57  self.enteringNumber = NO;
58  self.display.text = @"0";
59  [self.myBrain clear];
60}
61@end