ios - UISearchBar issues Xcode 5 -

i having issues uisearchbar have implemented. app compile , run, hit search bar begin typing word in, crashes. can tell me if see wrong syntax? suppose go through states have in nsarray.

tableviewcontroller.h:

#import <uikit/uikit.h>  @interface tableviewcontroller : uitableviewcontroller <uisearchbardelegate>  @property (nonatomic, strong) nsmutablearray *results;  @property (nonatomic, strong) iboutlet uisearchbar *searchbar;  @end 

tableviewcontroller.m:

#import "tableviewcontroller.h" #import "viewcontroller.h"  @interface tableviewcontroller ()  @end  @implementation tableviewcontroller { nsarray *states; }  - (nsmutablearray *)results { if (!_results) {     _results = [[nsmutablearray alloc] init]; } return _results; }  - (id)initwithstyle:(uitableviewstyle)style { self = [super initwithstyle:style]; if (self) {     // custom initialization } return self; }  - (void)viewdidload { [super viewdidload];  states = [nsarray arraywithobjects:@"alabama", @"georgia", @"tennessee", @"colorado", nil]; }  - (void)didreceivememorywarning { [super didreceivememorywarning]; // dispose of resources can recreated. }  - (void)searchthroughdata { self.results = nil;  nspredicate *resultspredicate = [nspredicate predicatewithformat:@"self contains [search] $@", self.searchbar.text];  self.results = [[states filteredarrayusingpredicate:resultspredicate] mutablecopy]; }  - (void)searchbar:(uisearchbar *)searchbar textdidchange:(nsstring *)searchtext { [self searchthroughdata]; }  - (nsinteger)numberofsectionsintableview:(uitableview *)tableview { return 1; }  - (nsinteger)tableview:(uitableview *)tableview numberofrowsinsection:(nsinteger)section { if(tableview == self.tableview) {     return [states count]; }  else {     [self searchthroughdata];     return self.results.count; } }   - (uitableviewcell *)tableview:(uitableview *)tableview cellforrowatindexpath:(nsindexpath *)indexpath { static nsstring *cellidentifier = @"cell"; uitableviewcell *cell = [tableview dequeuereusablecellwithidentifier:cellidentifier];  if (!cell) {     cell = [[uitableviewcell alloc] initwithstyle:uitableviewcellstyledefault  reuseidentifier:cellidentifier];     cell.accessorytype = uitableviewcellaccessorydisclosureindicator; }  if(tableview == self.tableview) {     cell.textlabel.text = [states objectatindex:indexpath.row]; }  else {     cell.textlabel.text = self.results[indexpath.row]; }  return cell; } 

i new objective-c, sorry if simple question should know answer to.

thanks

the first line of - (void)searchthroughdata method sets nsmutablearray nil. may problem.