iphone - Sending NSString to viewController returns a null -

i sent nsstring viewcontroller, tried log viewcontroller, , turned null. code below

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edit: im deleting code , showing code application. because still getting (null)

habitviewcontroller.h

 #import <uikit/uikit.h>  @interface habitviewcontroller : uitableviewcontroller {      nsstring *cellname2;  }  @property(nonatomic,retain) nsstring *cellname2;  @end 

habitviewcontroller.m

@synthesize cellname2;  - (void)viewdidload {     [super viewdidload];      nslog(@"%@",cellname2);  } 

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detailviewcontroller.h

#import <uikit/uikit.h>  @interface detailviewcontroller : uiviewcontroller {      nsstring *cellname; } @property(nonatomic,retain) nsstring *cellname;  @end 

detailviewcontroller.m

#import "detailviewcontroller.h"  #import "habitviewcontroller.h"  @end  @implementation detailviewcontroller  @synthesize cellname;  #pragma mark - managing detail item  - (void)viewdidload {     [super viewdidload];      cellname = @"hello world";      habitviewcontroller *obj = [[habitviewcontroller alloc] init];      obj.cellname2 = cellname; } 

i left lot of code out, because had nothing problem.

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edit

based on jsdodgers comments , answer, have updated question :

habitviwcontroller.h

#import <uikit/uikit.h>  @interface habitviewcontroller : uitableviewcontroller {  }  @property(nonatomic,retain) nsstring *cellname2;  @end 

.m

- (void)viewdidload {     [super viewdidload];      nslog(@"%@",self.cellname2);  } 

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detailviewcontroller.h

#import <uikit/uikit.h>  @interface detailviewcontroller : uiviewcontroller {  } @property(nonatomic,retain) nsstring *cellname;  @end 

.m

@synthesize cellname;  - (void)viewdidload {     [super viewdidload];      cellname = @"hello world";      habitviewcontroller *obj = [[habitviewcontroller alloc] init];      obj.cellname2 = self.cellname;      [self configureview];   } 

but still dont have success. still says (null)

this because have 2 different variables in receiverviewcontroller.

one of them called cellname2, creating through nsstring *cellname2. other called _cellname2 creating through @property(nonatomic,retain) nsstring *cellname2;.

the first can call in receiverviewcontroller through cellname2.... second, can call through either _cellname2... or self.cellname2.

when obj.cellname2 = ..., setting _cellname2, not cellname2. thus, when print cellname2, correctly null have not set yet.

i suggest removing nsstring *cellname2; code. same goes cellname in other class.