[obj-c] Casting, 캐스팅, 데이터형변환

* BOOL -> Object화

[NSNumber numberWithBool:<#(BOOL)#>]

*int, float, double -> Object화

[NSNumber number〜...  ]

*NSString -> NSNumber

[NSNumber numberWithInteger:[theString integerValue]];

http://stackoverflow.com/questions/3163652/how-to-convert-nsstring-to-nsnumber-without-using-numberfromstring