ios - Updating UILabel in Child View 1 after Global Variable Update in Child View 2 -

i have made simple app test , cannot figure out. have ipad storyboard have put 2 container views shown below. have label in 1 view , button in another. button increment label, 1 number @ time.

my problem not passing value or incrementing, getting view load new value. each container has own viewcontroller

some code below, although sparse ive written bunch , deleted didn't work. please correct format. keep general format, updating global variable within button , updating label.

labelviewcontroller.h  #import <uikit/uikit.h>  @interface labelviewcontroller : uiviewcontroller @property (weak, nonatomic) iboutlet uilabel *checklabel;  -(void)loadlabel;  @end 

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labelviewcontroller.m #import "labelviewcontroller.h" #import "parentviewcontroller.h"  @interface labelviewcontroller ()  @end  @implementation labelviewcontroller @synthesize checklabel; -(void)loadlabel{     checklabel.text = [nsstring stringwithformat:@"%d",value];     [self.view setneedsdisplay]; } - (void)viewdidload {     [self loadlabel];     [super viewdidload]; } 

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buttonviewcontroller.h #import <uikit/uikit.h>   @interface buttonviewcontroller : uiviewcontroller - (ibaction)checkbutton:(id)sender; @end 

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buttonviewcontroller.m #import "buttonviewcontroller.h" #import "parentviewcontroller.h" #import "labelviewcontroller.h"  @interface buttonviewcontroller ()  @end  @implementation buttonviewcontroller - (ibaction)checkbutton:(id)sender {     value++;     nslog(@"%d",value);     labelviewcontroller *fnc = [[labelviewcontroller alloc] init];     [fnc loadlabel]; } - (void)viewdidload {     [super viewdidload]; } 

picture at: http://farm4.staticflickr.com/3822/9469907420_746db25b23_b.jpg

in buttonviewcontroller, don't want alloc init'ing instance of labelviewcontroller -- 1 that's on screen exists. both child view controllers instantiated before parent controller is. so, need reference labelviewcontroller that's on screen. can self.parentviewcontroller.childviewcontrollers[0] (that 0 might have 1 -- don't know controller which).

 labelviewcontroller *fnc = self.parentviewcontroller.childviewcontrollers[0];  [fnc loadlabel];