objective-c 装箱和拆箱

NSNumber:

1、装箱

+ (NSNumber*) numberWitChar: (char) value;

+ (NSNumber*) numberWithInt: (char) value;

+ (NSNumber*) numberWithFloat: (float) value;

+ (NSNumber*) numberWithBool: (BOOL) value;

2、拆箱

-  (char) charValue;

-  (int) intValue;

-  (float) floatValue;

-  (BOOL) boolValue;

- (NSString*) stringValue;