OC-NSNumber与NSValue

//主要作用:

//由于OC中NSArray\NSDictionary中只能存储对象

//那么NSNumber就是用来把int\float\double等转换成对象

NSNumber * nb=[NSNumber numberWithInt:5];

NSArray * [email protected][nb];

NSNumber * nb2=arr.firstObject;

int a=nb2.intValue;

NSNumber * [email protected];

NSArray *[email protected][n];

NSNumber *n2=array.lastObject;

NSLog(@"%f",n2.floatValue);

//NSNumber继承NSValue

//NSValue是把结构体转换成对象

CGPoint cg=NSMakePoint(4, 5);

NSValue *value=[NSValue valueWithPoint:cg];

NSArray * [email protected][value];

NSValue * rel=arr2.firstObject;

CGPoint c=rel.pointValue;