#import <Foundation/Foundation.h>// : NSObject 目的是：让Car这个类具备创建对象的能力@interface Car : NSObject{    // 用来声明对象属性（实例变量\成员变量，默认会初始化为0）    // @public可以让外部的指针间接访问对象内部的成员变量    int wheels;    int speed;}@end@implementation Car@endint  main(){    [Car new];      c->wheels = 4;    c->speed = 200;       return 0;}

#import <Foundation/Foundation.h>@interface Person : NSObject{    @public    int age;    double weight;}- (void)walk;- (void)eat;@end@implementation Person- (void)walk{    NSLog(@"%d岁、%f公斤的人走了一段路", age, weight);}- (void)eat{    NSLog(@"%d岁、%f公斤的人在吃东西", age, weight);}@endint main(){    // 在使用类创建对象之前，会将类加载进内存    Person *p = [Person new];    p->age = 20;    p->weight = 40;        [p eat];    [p walk];        Person *p2 = [Person new];    p2->age = 30;    p2->weight = 60;    [p2 eat];    [p2 walk];        return 0;}