提高ptr_map替换值 [英] boost ptr_map replacing the value

问题描述

给出一个键，我试图替换一个值.对于不使用指针的常规地图，我只使用了以下调用

Given a key, I am trying to replace a value. With regular maps, that do not use pointers, I simply used the following call

iter->second = object; //Where object was passed in by reference

如何使用boost :: ptr_map实现相同的目标?这里的概念是，我们使用派生对象替换整个类

How do I achieve the same with boost::ptr_map? The concept here is that we replace the entire class using the derived_object

iter->second = derived_object; //derived_object is a base_object pointer

推荐答案

这可以解决问题:

the_map.replace(iter, derived_object);

the_map当然是iter指向的地图.

请注意，ptr_map<K,V>::replace返回一个ptr_map<K,V>::auto_type，因此您可以根据需要获取被替换的对象.当然，如果您忽略它，它会被自动破坏，并且您永远不需要知道它在那里.

Note that ptr_map<K,V>::replace returns a ptr_map<K,V>::auto_type, so you can grab the replaced object if you want. Of course, if you ignore it, it's automagically destroyed and you need never know it was there.

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