NSNumber

int i =100;

float f =3.14;

double db =66.6666;

BOOL bl =YES;

//包装成对象

NSNumber*number1 = [NSNumbernumberWithInt:i];

NSNumber*number2 = [NSNumbernumberWithFloat:f];

NSNumber*number3 = [NSNumbernumberWithDouble:dd];

NSNumber*number4 = [NSNumbernumberWithBool:bl];

NSArray*array =@[number1,number2,number3,number4];

NSLog(@"array = %@",array);

//取出下标为1的元素

NSNumber*n2 = array[1];

NSLog(@"%@",n2);

//拆包装，还原成最初的样子

float ff =[n2floatValue];

NSLog(@"ff = %.2f",ff);

//在Xcode4.6以后的新语法

//10,8.88,3.14,NO

NSArray*array1 =@[@10,@8.88,@3.14,@NO];

NSLog(@"array1 = %@",array1);

NSNumber*nn = array1[1];

doubled = [nndoubleValue];

NSLog(@"d = %.2lf",d);

Person*per = [[Personalloc]init];

per.age=20;

//把per这个对象的年龄保存到数组中

NSArray*array2 =@[@(per.age)];

NSLog(@"array2 = %@",array2);

#import

@interfacePerson :NSObject

@property(nonatomic,assign)intage;

@end

#import"Person.h"

@implementationPerson

@end