第二天（内存管理）

 1 #import "Person.h"
 2 
 3 @implementation Person
 4 
 5 - (void)dealloc
 6 {
 7     [super dealloc];
 8     NSLog(@"Person 被销毁了");
 9 }
10 
11 @end

1 #import <Foundation/Foundation.h>
2 
3 @interface Person : NSObject
4 
5 @end

  1 //内存管理原则(配对原则):只要出现了new,alloc,retain方法,就要配对出现release,autorelease
  2 //对象存入到自动释放池中,当这个池子被销毁的时候他会对池子中所有的对象进行一次release操作
  3 //怎么把对象存到池子中
  4 #import <Foundation/Foundation.h>
  5 #import "Person.h"
  6 
  7 int main(int argc, const char * argv[])
  8 {
  9     /* 示例1
 10     //自动释放池
 11     //大括号代表池子的作用域
 12     @autoreleasepool
 13     {
 14         
 15      //release 功能 retaincount - 1
 16      //autorelease 好像功能也是 retaincount - 1 ?
 17         //1
 18         Person * p = [[Person alloc] init];
 19 //        [p release];//retainCount立即 -1
 20         [p autorelease]; //autorelease方法的作用只是将对象放入到池子中,然后返回一个self
 21         
 22         NSLog(@"asdfasdf");
 23         
 24      }//代表,池子将要被销毁,对池子中所有的对象进行一次release操作,[p release] 0
 25      */
 26     
 27     /*
 28     //autoreleasepool我么可以自己随意的创建
 29     
 30     // 示例2
 31     //1//不管你这个对象时在@autoreleasepool 之内创建的还是在之外创建的,只要你在池子中调用了autorelease那么这个对象就会被放入到池子中
 32     Person * p = [[Person alloc ] init];
 33     
 34     @autoreleasepool {
 35         
 36         [p autorelease];
 37         
 38     }//p 0
 39     */
 40     // 示例3
 41     /*
 42     //1 只有在自动释放池的作用域中调用对象的autorelease方法才能够正确的讲对象放入到池子中
 43     Person * p = [[Person alloc] init];
 44     [p autorelease];
 45     
 46     NSLog(@"aaaa");
 47     @autoreleasepool {
 48         
 49     }
 50     NSLog(@"bbb");
 51      */
 52     //示例4
 53     /*
 54     // 1
 55     Person *  p = [[Person alloc] init];
 56     
 57     @autoreleasepool {
 58         
 59         [p autorelease];//加入第一次
 60         
 61         [p autorelease];//加入第二次
 62         
 63         NSLog(@"abc");
 64     }//[p release]0 [p release]
 65     
 66      NSLog(@"cbd");
 67     */
 68     
 69     //示例5
 70     /*
 71     //1
 72     Person * p = [[Person alloc] init];
 73     
 74     @autoreleasepool {
 75         
 76         @autoreleasepool {
 77             
 78             [p autorelease];
 79         }//?[p release] 0
 80         
 81     }
 82     */
 83     
 84     
 85     Person * p = [[Person alloc] init];
 86     
 87     @autoreleasepool {
 88         
 89         [p autorelease];
 90         
 91         @autoreleasepool {
 92             
 93          
 94             [p autorelease];
 95         }//[p release] 0
 96         
 97         
 98     }//[p release];
 99     
100     
101     return 0;
102 }

 1 #import "Chief.h"
 2 
 3 @implementation Chief
 4 
 5 - (void)dealloc
 6 {
 7     [super dealloc];
 8     NSLog(@"厨师被回收了");
 9 }
10 
11 + (Chief *)chief
12 {
13     /*
14     Chief * chi = nil;
15     
16     chi = [[Chief alloc] init];
17     
18 //    [chi release];
19     [chi autorelease];
20     */
21     
22     Chief * chi = [[self alloc] init];
23     
24     
25     return [chi autorelease];
26 }
27 - (Food *)chiefMakeFood
28 {
29    
30   
31     //如果在方法中创建一个对象,最好给我初始化为nil,防止出现野指针错误
32     // 1
33     Food * food = [[Food alloc] init];
34     food.name = @"凑豆乳";
35 //    // 0
36 //    [food release];
37     [food autorelease];
38     
39     return food;
40     
41 }
42 
43 @end

1 #import <Foundation/Foundation.h>
2 #import "Food.h"
3 
4 @interface Chief : NSObject
5 
6 + (Chief *)chief;
7 - (Food *)chiefMakeFood;
8 
9 @end

 1 #import "Food.h"
 2 
 3 @implementation Food
 4 - (void)dealloc
 5 {
 6     [super dealloc];
 7     [_name release];
 8     NSLog(@"Food被销毁了");
 9 }
10 
11 @end

1 #import <Foundation/Foundation.h>
2 
3 @interface Food : NSObject
4 
5 @property(nonatomic,retain) NSString * name;
6 
7 @end

 1 #import <Foundation/Foundation.h>
 2 #import "Chief.h"
 3 //autorelease笔试面试出现的几率比[release]
 4 
 5 int main(int argc, const char * argv[])
 6 {
 7 
 8     @autoreleasepool {
 9     
10         /*
11         Chief * chi  = [[Chief alloc] init];
12         Food * food = [chi makeFood];;
13 
14         
15         NSLog(@"%@",food.name);//[nil name];
16         
17         [chi release];
18         */
19         
20 
21         
22         Chief * chi = [Chief chief];
23         Food * food = [chi chiefMakeFood];
24         
25         NSLog(@"%@",food.name);
26         
27         NSString * name = [NSString stringWithFormat:@"%@",@"施瓦辛格"];//都是autorelease
28 
29         NSLog(@"%@",name);
30         
31     }
32     return 0;
33 }

 1 #import "Person.h"
 2 
 3 @implementation Person
 4 
 5 - (void)dealloc
 6 {
 7 //    [super dealloc];不能够在调用
 8 //      releae retain 在ARC机制中不能够在去手动调用
 9     NSLog(@"Person 被释放了");
10 }
11 
12 @end

1 #import <Foundation/Foundation.h>
2 
3 @interface Person : NSObject
4 
5 @end

 1 //ARC简单,不用程序员在去管理内存
 2 //1.强指针 Strong
 3 //2.弱指针 weak
 4 
 5 //只要有强指针指向一个对象,那么系统就不会回收该对象
 6 //只要没有强指针指向对象,系统立即回收该对象
 7 
 8 //弱指针不影响,对象被回收
 9 
10 //默认情况下,所有的指针都是强指针类型
11 
12 #import <Foundation/Foundation.h>
13 #import "Person.h"
14 
15 void test(Person * v)//Person * v =
16 {
17     v = nil;
18 }//
19 
20 int main(int argc, const char * argv[])
21 {
22 
23  
24         
25     /*
26         
27     Person * p = [[Person alloc] init];
28     
29 //    p = nil;
30     
31     Person * p1 = p;
32     
33     p = nil;
34    */
35     
36     
37     Person * p = [[Person alloc] init];
38     
39     test(p);
40     
41     p = nil;
42    
43     NSLog(@"adfasdf");
44     /*
45     //创建出来就会立即被释放掉,应为没有强指针指向该对象
46     __weak Person * p = [[Person alloc] init];
47     NSLog(@"adfadf");
48     */
49     
50     /*
51     Person * p = [[Person alloc] init];
52     
53     __weak Person * p1 = p;
54     
55     p = nil;
56     */
57     
58 
59     
60     return 0;
61 }

 1 #import "Person.h"
 2 
 3 @implementation Person
 4 
 5 -(void)dealloc
 6 {
 7     NSLog(@"person 被销毁了");
 8 }
 9 
10 @end

 1 #import <Foundation/Foundation.h>
 2 #import "Car.h"
 3 
 4 @interface Person : NSObject
 5 
 6 //@property(nonatomic,retain)Car * car;
 7 //ARC机制 strong 对象,手动内存管理的retain关键字,(一定能够都是应用在对象类型变量上)
 8 //ARC机制中的 weak 对象手动内存管理的assign关键字,(一定能够都是应用在对象类型变量上)
 9 @property (nonatomic,strong)Car * car;//强直阵类型的对象,会影响对象回收
10 @property (nonatomic,weak)Car * car2;// 弱指针类型的对象,不会影响对象的回收
11 //@property (nonatomic,assign)Car * car3;//造成迷惑,会导致许多程序员搞不清这个变量到底是stong类型的还是weak类型
12 
13 @property (nonatomic,strong)NSString * name;
14 @property (nonatomic,strong)NSString * idCard;
15 
16 //ARC机制下 基本数据类型的@property参数使用,与手动内存管理完全一致
17 @property (nonatomic,assign)int age;
18 
19 @end

1 #import "Car.h"
2 
3 @implementation Car
4 - (void)dealloc
5 {
6     NSLog(@"Car 被销毁了");
7 }
8 @end

1 #import <Foundation/Foundation.h>
2 
3 @interface Car : NSObject
4 
5 @end

 1 #import <Foundation/Foundation.h>
 2 
 3 int main(int argc, const char * argv[])
 4 {
 5 
 6     @autoreleasepool {
 7         
 8         
 9     }
10     return 0;
11 }

1 #import "Person.h"
2 
3 @implementation Person
4 - (void)dealloc
5 {
6     NSLog(@"PErson 被销毁了");
7 }
8 @end

1 #import <Foundation/Foundation.h>
2 
3 @interface Person : NSObject
4 
5 @property (nonatomic,strong)NSString * name;
6 @property (nonatomic,strong)NSString * idCard;
7 
8 @end

 1 #import <Foundation/Foundation.h>
 2 
 3 int main(int argc, const char * argv[])
 4 {
 5 
 6     @autoreleasepool {
 7         
 8         // insert code here...
 9         NSLog(@"Hello, World!");
10         
11     }
12     return 0;
13 }

 1 #import "Person.h"
 2 
 3 @implementation Person
 4 - (void)sendMessageByIphone:(Iphone *)phone
 5 {
 6     [phone sendMessageWithNumber:@"123124321"];
 7 }
 8 
 9 - (void)dealloc
10 {
11 //    [super dealloc];
12 }
13 @end

1 #import <Foundation/Foundation.h>
2 #import "Iphone.h"
3 
4 @interface Person : NSObject
5 
6 - (void)sendMessageByIphone:(Iphone *)phone;
7 
8 @end

 1 #import "Iphone.h"
 2 
 3 @implementation Iphone
 4 
 5 - (void)dealloc
 6 {
 7     [super dealloc];
 8     [_name release];
 9     NSLog(@"Iphone 被销毁了");
10 }
11 
12 
13 - (void)sendMessageWithNumber:(NSString *)number
14 {
15     NSLog(@"发消息给 %@",number);
16 }
17 @end

1 #import <Foundation/Foundation.h>
2 
3 @interface Iphone : NSObject
4 
5 @property (nonatomic,retain)NSString * name;
6 
7 - (void)sendMessageWithNumber:(NSString *)number;
8 
9 @end

 1 #import <Foundation/Foundation.h>
 2 #import "Person.h"
 3 
 4 int main(int argc, const char * argv[])
 5 {
 6 
 7     @autoreleasepool {
 8         
 9 
10         
11     }
12     return 0;
13 }

 1 #import "Iphone.h"
 2 
 3 @implementation Iphone
 4 
 5 - (void)dealloc
 6 {
 7     [super dealloc];
 8     [_name release];
 9     NSLog(@"Iphone 被销毁了");
10 }
11 
12 
13 - (void)sendMessageWithNumber:(NSString *)number
14 {
15     NSLog(@"发消息给 %@",number);
16 }
17 @end

1 #import <Foundation/Foundation.h>
2 
3 @interface Iphone : NSObject
4 
5 @property (nonatomic,retain)NSString * name;
6 
7 - (void)sendMessageWithNumber:(NSString *)number;
8 
9 @end

 1 #import <Foundation/Foundation.h>
 2 
 3 int main(int argc, const char * argv[])
 4 {
 5 
 6     @autoreleasepool {
 7         
 8         // insert code here...
 9         NSLog(@"Hello, World!");
10         
11     }
12     return 0;
13 }

 1 #import "Person.h"
 2 
 3 @implementation Person
 4 
 5 -(void)dealloc
 6 {
 7     NSLog(@"Person 被销毁了");
 8 }
 9 
10 @end

1 #import <Foundation/Foundation.h>
2 #import "Car.h"
3 
4 @interface Person : NSObject
5 
6 @property (nonatomic,strong)Car * car;
7 
8 @end

 1 #import "Car.h"
 2 #import "Person.h"
 3 
 4 @implementation Car
 5 
 6 - (void)dealloc
 7 {
 8     NSLog(@"Car 被销毁了");
 9 }
10 
11 @end

 1 import <Foundation/Foundation.h>
 2 //#import "Person.h"
 3 @class Person;
 4 
 5 @interface Car : NSObject
 6 
 7 //@property (nonatomic,strong)Person * p;
 8 
 9 //当出现类循环应用的时候,只需要把一方面的Strong引用改为weak,并且在.h文件中使用@class 类名的方式,通知.h文件类的存在
10 @property (nonatomic,weak)Person * p;
11 
12 @end

 1 #import <Foundation/Foundation.h>
 2 #import "Person.h";
 3 
 4 int main(int argc, const char * argv[])
 5 {
 6 
 7     @autoreleasepool {
 8         
 9         Person * p = [[Person alloc] init];
10         
11         Car * car = [[Car alloc] init];
12         
13         [p setCar:car];
14         
15         [car setP:p];
16         
17         p = nil;
18         
19         car = nil;
20         
21         NSLog(@"agfadsgf");
22     }
23     return 0;
24 }