iOS ARC MRC情况下重写setter getter方法

MRC：

@interface People : NSObject  @property (nonatomic,retain) NSArray *oneArr;  @end 

setter:- (void)setOneArr:(NSArray *)oneArr{      if (_oneArr != oneArr) {          [oneArr release];          _oneArr = [oneArr retain];//或者copy视情况而定      }  }  getter:- (NSArray *)oneArr{      if (!_oneArr) {          _oneArr = @[@"1",@"2",@"3"];      }      return [[_oneArr retain] autorelease];  }  

ARC:

@interface People : NSObject    @property (nonatomic,strong) NSArray *twoArr;  @end

setter:- (void)setTwoArr:(NSArray *)twoArr{      if (_twoArr != twoArr) {          _twoArr = twoArr;      }  } getter:  - (NSArray *)twoArr{      if (!_twoArr) {          self.twoArr = @[@"1",@"2",@"3"];      }      return _twoArr;  }