cocoooooa的专栏

The format specifiers supported by the NSString formatting methods and CFString formatting functions follow the IEEE printf specification; the specifiers are summarized in Table 1. Note that you can

NSNumber + (NSNumber *)numberWithInt:(int)value; + (NSNumber *)numberWithDouble:(double)value; - (int)intValue; - (double)doubleValue; NSNumber可以将基本数据类型包装起来，形成一个对象，这样就可以给其发送消息，装入NSArray中等等。 NS