OC ARC之循环引用问题（代码分析）

 //
 //  main.m
 //  03-arc-循环引用
 //
 //  Created by apple on 13-8-11.
 //  Copyright (c) 2013年 itcast. All rights reserved.
 //

 #import <Foundation/Foundation.h>

 @class Dog;

 @interface Person : NSObject

 @property (nonatomic, strong) Dog *dog;

 @end

 #import "Person.h"

 @implementation Person

 - (void)dealloc
 {
     NSLog(@"Person--dealloc");
 }

 @end

 #import <Foundation/Foundation.h>

 @class Person;

 @interface Dog : NSObject

 @property (nonatomic, weak) Person *person;

 @end

 #import "Dog.h"

 @implementation Dog
 - (void)dealloc
 {
     NSLog(@"Dog--dealloc");
 }
 @end

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

 /*
  当两端循环引用的时候，解决方案：
  1> ARC
  1端用strong，另1端用weak

  2> 非ARC
  1端用retain，另1端用assign
  */

 int main()
 {
     Person *p = [[Person alloc] init];

     Dog *d = [[Dog alloc] init];
     p.dog = d;
     d.person = p;

     return ;
 }