Objective-c语言_内存管理2(代码)

来源：互联网发布：mac pro截屏快捷键编辑：程序博客网时间：2024/06/07 10:47

在XCode4.2以上的版本为ARC（自动引用计数）也就是会自动释放不需要的内存

所有在Xcode4.2以上的版本使用MRC得在

=========>在文本框里的大上-fno-objc-arc

#import "ViewController.h"

#import "Student.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

NSMutableArray *array1 = [NSMutableArray array];

NSMutableArray *array2 = [NSMutableArray array];

[array1 addObject:array2];

[array2 addObject:array1];

//上面这个测试重复引用

//下面测试内存泄露

Student *student1=[[Student alloc]init];

NSLog(@"count1=%lu",(unsigned long)[student1 retainCount]);

Student *student2=[[Student alloc]init];

NSLog(@"count2=%lu",(unsigned long)[student2 retainCount]);

[student1 release];

NSLog(@"count1=%lu",(unsigned long)[student1 retainCount]);

Student *student3=[student2 copy];

NSLog(@"count3=%lu",(unsigned long)[student3 retainCount]);

if (student2 == student3)

{

NSLog(@"相同");

}

Student *student4=[student2 mutableCopy];

NSLog(@"count5=%lu",(unsigned long)[student4 retainCount]);//等于1

NSString *string=[NSString stringWithFormat:@"ppp"];

NSString *string1=[string copy];

if (string == string1)

{

NSLog(@"%lu,%lu",(unsigned long)[string retainCount],[string1 retainCount]);

}

NSMutableString *mstring=[NSMutableString stringWithFormat:@"ddd"];

NSMutableString *mstring1=[mstring copy];

NSLog(@"%lu,%lu",(unsigned long)[mstring retainCount],[mstring1 retainCount]);

//当我们将一个对象加入到集合（如数组，字典和set集合）中时，集合会拥有该对象的所有权，当集合移除该对象

//或者集合本身被清理是，集合会放弃对象的所有权

NSMutableArray *array=[NSMutableArray array];

for (int i=0; i<10; i++)

{

Student *stu=[Student new];

[array addObject:stu];

[stu release];

}

Student *st=[Student new];

[st release];

NSLog(@"%lu",(unsigned long)[st retainCount]);//本来预期输出是0为什么在这里会输出1呢

//已经释放的对象发送NSLog发送了一个消息

//在最后一次执行马上就要回收和就没有必有-1了不减1加快对象的释放

[student2 release];

[student3 release];

[student4 release];

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

@end

在上面的代码通过Xcode->最上面的导航栏Product->Profile

会看的这张图片右边的图标

然后选择第二行第六个叫“Leaks”用来测试重复调用和内存泄露

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