Objective-C - 循环引用问题

循环引用问题

/* 1.@class的作用：仅仅告诉编译器，某个名称是一个类 @class Person; // 仅仅告诉编译器，Person是一个类 2.开发中引用一个类的规范 1> 在.h文件中用@class来声明类 2> 在.m文件中用#import来包含类的所有东西 3.两端循环引用解决方案 1> 一端用retain 2> 一端用assign */#import <Foundation/Foundation.h>#import "Card.h"#import "Person.h"int main(){    // p - 1    Person *p = [[Person alloc] init];    // c - 1    Card *c = [[Card alloc] init];    // c - 2    p.card = c;    // p - 1    c.person = p;    // c - 1    [c release];    // p - 0  c - 0    [p release];    return 0;}

#import "Card.h"// @class仅仅是告诉编译器，Card是一个类//@class Card;@interface Person : NSObject@property (nonatomic, retain) Card *card;@end

#import "Card.h"@implementation Person- (void)dealloc{    NSLog(@"Person被销毁了");    [_card release];    [super dealloc];}@end

@class Person;@interface Card : NSObject@property (nonatomic, assign) Person *person;@end

@implementation Card- (void)dealloc{    NSLog(@"Car被销毁了");    // [_person release];    [super dealloc];}@end