oc46--nonatomic, retain

//
//  Person.h

#import <Foundation/Foundation.h>
#import "Room.h"
#import "Car.h"
#import "Dog.h"

@interface Person : NSObject
{
    Room *_room;
    Car *_car;
    Dog *_dog;
}
/*
- (void)setRoom:(Room *)room;
- (void)setCar:(Car *)car;
- (void)setDog:(Dog *)dog;

- (Room *)room;
- (Car *)car;
- (Dog *)dog;
 */
@property(nonatomic, retain) Room *room;//标准写法都是(nonatomic, retain)

/*
 写了retain就可以生成：
 - (void)setRoom:(Room *)room
 {
     // 1.判断传入的对象和当前对象是否一样
     if (_room != room) {
         // 2.release以前的对象
         [_room release];
         // 3.retain传入的对象
         _room = [room retain];
     }
 }
 */

/*
 readonly: 只会生成getter方法
 readwrite: 既会生成getter也会生成setter, 默认什么都不写就是readwrite

 getter: 可以给生成的getter方法起一个名称
 setter: 可以给生成的setter方法起一个名称

 retain: 就会自动帮我们生成getter/setter方法内存管理的代码，上次44，45的内容
 assign: 不会帮我们生成set方法内存管理的代码, 仅仅只会生成普通的getter/setter方法, 默认什么都不写就是assign。

 多线程
 atomic ：性能低（默认）
 nonatomic ：性能高
 在iOS开发中99.99%都是写nonatomic，因为手机性能低。 atomic用于pc开发中。
*/
@end

//
//  Person.m

#import "Person.h"

@implementation Person

/*
- (void)setRoom:(Room *)room
{
    // 1.判断传入的对象和当前对象是否一样
    if (_room != room) {
        // 2.release以前的对象
        [_room release];
        // 3.retain传入的对象
        _room = [room retain];
    }
}
- (void)setCar:(Car *)car
{
    if (_car != car) {
        [_car release];
        _car = [car retain];
    }
}
- (void)setDog:(Dog *)dog
{
    if (_dog != dog) {
        [_dog release];
        _dog = [dog retain];
    }
}

- (Room *)room
{
    return _room;
}
- (Car *)car
{
    return _car;
}
- (Dog *)dog
{
    return _dog;
}
 */

- (void)dealloc
{
    [_room release];
    [_car release];
    [_dog release];

    NSLog(@"%s", __func__);
    [super dealloc];
}
@end

//
//  main.m
//  property修饰符

#import <Foundation/Foundation.h>
#import "Person.h"

int main(int argc, const char * argv[]) {

    Person *p = [Person new];

    Room *r = [Room new];

    /*
//    Car *c =[Car new];
//    Dog *d = [Dog new];

//    p.room = r;
//    p.car = c;
//    p.dog = d;

//    [d release];
//    [c release];
//    [r release];
//    [p release];
     */

    p.room = r;
    [r release];

    // 换房了, 如果set方法中没有release旧值, 就会内存泄露
    Room *r2 = [Room new];
    p.room = r2;
    [r2 release];

    // 重复赋值
    p.room = r;

    [p release];
    return 0;
}