//
// Person.h
// OC7_复合类内存管理(setter方法)
//
// Created by zhangxueming on 15/6/18.
// Copyright (c) 2015年 zhangxueming. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "Dog.h"
@interface Person : NSObject
{
Dog *
_dog;
}
- (Dog *
)dog;
- (
void)setDog:(Dog *
)dog;
@end
//
// Person.m
// OC7_复合类内存管理(setter方法)
//
// Created by zhangxueming on 15/6/18.
// Copyright (c) 2015年 zhangxueming. All rights reserved.
//
#import "Person.h"
@implementation Person
- (Dog *
)dog
{
return _dog;
}
//方法一:
//- (void)setDog:(Dog *)dog
//{
// _dog = dog;
//}
//方法二:
//- (void)setDog:(Dog *)dog
//{
// _dog = [dog retain];
//}
//方法三:
- (
void)setDog:(Dog *)dog
//xiaoHei _dog count = 1;
{
[_dog release];//0
// NSLog(@"lajfalfjal");
// NSLog(@"jslfjslfjl");
// NSLog(@"lajfalfjal");
// NSLog(@"jslfjslfjl");
// NSLog(@"lajfalfjal");
// NSLog(@"jslfjslfjl");
// NSLog(@"lajfalfjal");
// NSLog(@"jslfjslfjl");
// NSLog(@"lajfalfjal");
// NSLog(@"jslfjslfjl");
// NSLog(@"lajfalfjal");
// NSLog(@"jslfjslfjl");
// NSLog(@"lajfalfjal");
// NSLog(@"jslfjslfjl");
// NSLog(@"lajfalfjal");
// NSLog(@"jslfjslfjl");
_dog =
[dog retain];
}
//标准写法
//- (void)setDog:(Dog *)dog
//{
// if (_dog!=dog) {
// [_dog release];
// _dog = [dog retain];
// }
//}
- (
void)dealloc
{
[_dog release];
[super dealloc];
}
@end
//
// Dog.h
// OC7_复合类内存管理(setter方法)
//
// Created by zhangxueming on 15/6/18.
// Copyright (c) 2015年 zhangxueming. All rights reserved.
//
#import <Foundation/Foundation.h>
@interface Dog : NSObject
@end
//
// Dog.m
// OC7_复合类内存管理(setter方法)
//
// Created by zhangxueming on 15/6/18.
// Copyright (c) 2015年 zhangxueming. All rights reserved.
//
#import "Dog.h"
@implementation Dog
//-(void)dealloc
//{
// //NSLog(@"12321313");
// [super dealloc];
//}
@end
//
// main.m
// OC7_复合类内存管理(setter方法)
//
// Created by zhangxueming on 15/6/18.
// Copyright (c) 2015年 zhangxueming. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "Dog.h"
#import "Person.h"
int main(
int argc,
const char *
argv[]) {
@autoreleasepool {
Dog *xiaoBai =
[[Dog alloc] init];
Person *xiaoXin =
[[Person alloc] init];
//方法一: 不ok，人并没有真正持有狗，如果在main函数里[xiaoBai release]，让dog的引用计数减1，就变为0，dog就销毁了
// xiaoXin.dog = xiaoBai;
// NSLog(@"retainCount = %li", xiaoBai.retainCount);
// [xiaoBai release];//
// [xiaoXin release];
//方法二:
//不ok，如果人再持有别的狗，就会造成第一条狗得不到释放，内存泄露。
// xiaoXin.dog = xiaoBai;
// NSLog(@"xiaoBai retainCount = %li", xiaoBai.retainCount);
// Dog *xiaoHei = [[Dog alloc] init];
// xiaoXin.dog = xiaoHei;
// [xiaoBai release];
// [xiaoHei release];
// [xiaoXin release];
//方法三:不ok，如果本来持有一条狗，又重新设置这条狗，先进行release，这个时候，很可能dog就销毁了，然后，就没法再次retain了。
xiaoXin.dog =
xiaoBai;
Dog *xiaoHei = xiaoBai;
//[xiaoBai retain]
NSLog(
@"xiaoHei retainCount = %li", xiaoBai.retainCount);
[xiaoBai release];
NSLog(@"xiaoHei retainCount = %li", xiaoHei.retainCount);
xiaoXin.dog =
xiaoHei;
[xiaoXin release];
}
return 0;
}
转载于:https://www.cnblogs.com/0515offer/p/4586959.html
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