修改说明

README.md

@@ -1,3 +1,29 @@
 # AssociatedObjects
 
 我的博文[《Objective-C Associated Objects 的实现原理》](http://blog.leichunfeng.com/blog/2015/06/26/objective-c-associated-objects-implementation-principle/)的完整配套代码。
+
+``` objc
+__weak NSString *string_weak_assign = nil;
+__weak NSString *string_weak_retain = nil;
+__weak NSString *string_weak_copy   = nil;
+
+@implementation ViewController
+
+- (void)viewDidLoad {
+    [super viewDidLoad];
+
+    self.associatedObject_assign = [NSString stringWithFormat:@"leichunfeng1"];
+    self.associatedObject_retain = [NSString stringWithFormat:@"leichunfeng2"];
+    self.associatedObject_copy   = [NSString stringWithFormat:@"leichunfeng3"];
+
+    string_weak_assign = self.associatedObject_assign;
+    string_weak_retain = self.associatedObject_retain;
+    string_weak_copy   = self.associatedObject_copy;
+}
+
+- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
+//    NSLog(@"self.associatedObject_assign: %@", self.associatedObject_assign); // Will Crash
+    NSLog(@"self.associatedObject_retain: %@", self.associatedObject_retain);
+    NSLog(@"self.associatedObject_copy:   %@", self.associatedObject_copy);
+}
+```