title: Add decimal point for my Calculator
body: <p>I'm trying to make a calculator. Everything works fine, but now I want to add a decimal point and I do not know how. Can you please help? Thank you.</p>
  
  <p>I tried this</p>
  
  <pre><code>- (IBAction) buttondecimal {
      SelectNumber = SelectNumber * 10;
      SelectNumber = SelectNumber + @".";
      Screen.text = [NSString stringWithFormat: @"%0.f", SelectNumber]; }
  </code></pre>
  
  <p>, but I get an error: Invalid operands to binary expression ('double' and 'NSString *')</p>
  
  <p><strong>Here is my code:</strong></p>
  
  <p><strong>.h</strong> </p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  
  int Method;
  double SelectNumber;
  double RunningTotal;
  
  @interface KalkulackaViewController : UIViewController
  {
  IBOutlet UILabel *deglabel;
  IBOutlet UIButton *degbutton;
  IBOutlet UITextField *Screen;
  }
  
  -(IBAction)Number1:(id)sender;
  -(IBAction)Nasobeni:(id)sender;
  -(IBAction)Deleni:(id)sender;
  -(IBAction)Minus:(id)sender;
  -(IBAction)Plus:(id)sender;
  -(IBAction)Rovnase:(id)sender;
  -(IBAction)AllClear:(id)sender;
  
  @end
  </code></pre>
  
  <p><strong>.m</strong></p>
  
  <pre><code>#import "KalkulackaViewController.h"
  
  @interface KalkulackaViewController ()
  
  @end
  
  @implementation KalkulackaViewController
  
  
  - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
  {
      self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
      if (self) {
          // Custom initialization
      }
      return self;
  }
  
  - (void)viewDidLoad
  {
      [super viewDidLoad];
  
      UIView *paddingView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10,10)];
      Screen.rightView = paddingView;
      Screen.rightViewMode = UITextFieldViewModeAlways;
      Screen.leftView = paddingView;
      Screen.leftViewMode = UITextFieldViewModeAlways;
  }
  -(IBAction)Number1:(id)sender
  {
      SelectNumber = SelectNumber * 10;
      SelectNumber = SelectNumber + 1;
      Screen.text = [NSString stringWithFormat:@"%0.f", SelectNumber];
  }
  - (IBAction) buttondecimal
  {
  
  }
  </code></pre>