我们应该在取消注册时删除观察者吗？

Question

Observer *o = New Observer();
Subject *s = new Subject() ;
s->register(o);

//Is it a good practice to delete the observer in the unregister function?
//I feel it is not. As the Observer object might still be in use,  for example , 
//it might be registered to another Subject. 
s->unregister(o);  

//So it is safe to rely on the client code to delete the object or rely on the smart pointer things
delete o;

我想确认关于谁应该删除观察者对象,我的上述理解是否正确.

Answer 1

我同意你的观察.在取消注册函数中删除观察者并不是一个好习惯 - 因为"创建资源的人必须负责删除资源"这一简单事实

这样可以避免

• 创作者所感知的魔术行为.
• 代码行为将被很好地定义 - 创建者必须删除.这将为理解新系统开发人员的开发奠定全面基础.

在所有具有不同术语的书籍中讨论了类似的主题.