第二个Object-C类程序

/*
人
类名：Person
属性（实例变量/成员变量）：体重、年龄
行为（方法）：走路、吃
*/

#import <Foundation/Foundation.h>

/*
1.类的声明
*成员变量
*方法的声明
*/
@interface Person : NSObject
{
@public
int age;
double weight;
}

- (void)walk;
- (void)eat;

@end

//2.类的实现
@implementation Person

//实现@interface中声明的方法
- (void)walk
{
NSLog(@"%d岁、%.2f公斤的人走了一段路！",age,weight);
}

- (void)eat
{
NSLog(@"%d岁、%.2f公斤的人在吃东西！",age,weight);
}

@end

int main()
{

//在使用类创建对象之前，会将类加载进内存，只会加载一次
Person *p  =   [Person new];
p->age = 20;
p->weight = 40;

Person *p2 =    [Person new];
p2->age =   30;
p2->weight  =   50;

p = p2;//p指向的对象地址空间转为指向p2

p->age = 40;

[p2 walk];

[p eat];
[p walk];

/*
Person *person_first = [Person new];
person_first->age   =   20;
person_first->weight    =   50.0;
[person_first walk];

Person *person_second = [Person new];
person_second->age   =   30;
person_second->weight    =   60.0;
[person_second walk];
*/
return 0;
}