4.4OC10-内存管理2-set方法的内存管理

例一：

main.m

// main.m

// OC10-内存管理2-set方法的内存管理

// Created by qwz on 13-12-9.

#import <Foundation/Foundation.h>

#import "Student.h"

#import "Book.h"

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

{

@autoreleasepool {

Student *stu = [[Student alloc] initWithAge:29];

Book *book = [[Book alloc] initWithPrice:3.5];

[book release];

[stu release];

}

return 0;

}

Student.h

// Student.h

// OC10-内存管理2-set方法的内存管理

// Created by liuyes on 13-12-9.

#import <Foundation/Foundation.h>

#import "Book.h"

@interface Student : NSObject

@propertyint age;

- (id)initWithAge:(int)age;

@propertyBook *book;

@end

Student.m

// Student.m

// OC10-内存管理2-set方法的内存管理

// Created by liuyes on 13-12-9.

#import "Student.h"

@implementation Student

#pragma mark 构造方法

- (id)initWithAge:(int)age{

if( self = [super init]){

_age = age;

}

returnself;

}

#pragma mark 回收对象

- (void)dealloc{

NSLog(@"student:%i 被销毁了", _age);

[super release];

}

@end

Book.h

// Book.h

// OC10-内存管理2-set方法的内存管理

// Created by liuyes on 13-12-9.

#import <Foundation/Foundation.h>

@interface Book : NSObject

@propertyfloat price; //价格

- (id)initWithPrice:(float)price;

@end

Book.m

// Book.m

// OC10-内存管理2-set方法的内存管理

// Created by liuyes on 13-12-9.

#import "Book.h"

@implementation Book

- (id)initWithPrice:(float)price{

if (self = [super init]){

_price = price;

}

returnself;

}

- (void)dealloc{

NSLog(@"book:%f 被销毁了", _price);

[super dealloc];

}

@end

运行结果

2013-12-09 17:04:29.679 OC10-内存管理2-set方法的内存管理[634:403] book:3.500000 被销毁了

2013-12-09 17:04:29.703 OC10-内存管理2-set方法的内存管理[634:403] student:29 被销毁了

---------------------------------

----------------------------------

例二：

main.m

// main.m

// OC10-内存管理2-set方法的内存管理

// Created by qwz on 13-12-9.

#import <Foundation/Foundation.h>

#import "Student.h"

#import "Book.h"

void test(Student *stu){

//book:1

Book *book = [[Book alloc] initWithPrice:3.5];

//book:2

stu.book = book;

//book:1

[book release];

Book *book2 = [[Book alloc] initWithPrice:4.5];

//book2:2

stu.book = book2;

//book2:1

[book2 release];

}

void test1(Student *stu){

[stu readBook];

}

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

{

@autoreleasepool {

//stu:1

Student *stu = [[Student alloc] initWithAge:29];

//stu:1

//book:1

//book2:1

test(stu);

//stu:1

//book:1

//book2:1

test1(stu);

//stu:0

//book:0

[stu release];

}

return 0;

}

Student.h

// Student.h

// OC10-内存管理2-set方法的内存管理

// Created by liuyes on 13-12-9.

#import <Foundation/Foundation.h>

#import "Book.h"

@interface Student : NSObject{

Book *_book;

}

@propertyint age;

- (id)initWithAge:(int)age;

@propertyBook *book;

- (void)readBook;

@end

Student.m

// Student.m

// OC10-内存管理2-set方法的内存管理

// Created by liuyes on 13-12-9.

#import "Student.h"

@implementation Student

#pragma mark 构造方法

- (id)initWithAge:(int)age{

if( self = [super init]){

_age = age;

}

returnself;

}

#pragma mark 回收对象

- (void)dealloc{

//释放对象

[_book release];

//[self.book release];

NSLog(@"student:%i 被销毁了", _age);

[super dealloc];

}

#pragma mark - getter和setter方法

//@synthesize book = _book;

//如果自己手动实现了getter和setter，xcode就不会自动生成@synthesize

//也就不会自动生成_book

//getter和setter的默认实现

- (void)setBook:(Book *)book{

if(_book != book){

//先释放旧的成员变量

[_book release];

//在retain新传进来的对象

_book = [book retain];

}

- (Book *)book{

return _book;

}

#pragma mark - 公共方法

#pragma mark 读书

- (void)readBook{

NSLog(@"当前读的书是：%f", _book.price);

}

@end

Book.h

// Book.h

// OC10-内存管理2-set方法的内存管理

// Created by liuyes on 13-12-9.

#import <Foundation/Foundation.h>

@interface Book : NSObject

@propertyfloat price; //价格

- (id)initWithPrice:(float)price;

@end

Book.m

// Book.m

// OC10-内存管理2-set方法的内存管理

// Created by liuyes on 13-12-9.

#import "Book.h"

@implementation Book

- (id)initWithPrice:(float)price{

if (self = [super init]){

_price = price;

}

returnself;

}

- (void)dealloc{

NSLog(@"book:%f 被销毁了", _price);

[super dealloc];

}

@end

4.4OC10-内存管理2-set方法的内存管理

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