//動態(tài)創(chuàng)建類

        //1.使用objc_allocateClassPair創(chuàng)建一個類Class
        const char *className = "Person";
        Class class = objc_getClass(className);
        if(!class){
            Class superClass = [NSObject class];
            class = objc_allocateClassPair(superClass, className, 0);
        }
        
        //2.現(xiàn)在可以使用自定義的Person類
        id instance = [[class alloc] init];
        
        //3.給instance類添加一個屬性name，并且賦值
        objc_setAssociatedObject(instance, "name", @"Victor John", OBJC_ASSOCIATION_COPY_NONATOMIC);
        
        //給description屬性設(shè)置
        objc_setAssociatedObject(instance, "description", @"Person類的description", OBJC_ASSOCIATION_COPY_NONATOMIC);
        
        //4.然后獲取值
        id name = objc_getAssociatedObject(instance, "name");
        id description = objc_getAssociatedObject(instance, "description");
        
        //5.輸出打印
        NSLog(@"Person=%p, name=%@ ,description=%@", class, name, description);