vault backup: 2022-06-08 13:52:41

Affected files:
02. PARA/03. Resources（資源）/C++17/rvalue.md

02. PARA/03. Resources（資源）/C++17/rvalue.md

@@ -9,20 +9,6 @@ int c{5};
 int&& rtepm {c + 3};
 ```
 
-關於lvalue、rvalue的分別可以參考[Value categories - cppreference.com](https://en.cppreference.com/w/cpp/language/value_category)，或是[rvalue 參考](https://openhome.cc/Gossip/CppGossip/RvalueReference.html)等文章。這邊講用法跟好處。
-rvalue reference可以減少無間的複製成本。例如：
-```cpp
-std::string longStr = "qwertyuiopasdfghjklzxcbnm";
-std::string anotherLong = longStr;
-```
-這時longStr會被複製一份anotherLong，把longStr換成很大的buffer，其複製成本就更大了。用rvalue reference可以消除這個複製成本。如下：
-```cpp
-std::string longStr = "qwertyuiopasdfghjklzxcbnm";
-std::string&& anotherLong = longStr;
-
-std::cout << anotherLong; // "qwertyuiopasdfghjklzxcbnm"
-//std::cout << longStr;   // Undefined bahavior, don't do this
-```
-上面的例子，longStr的內容被「轉移」給anotherLong，所以不可以再longStr，這時候longStr的內容取決於move operator的作法。
-
-不過
+## 參考
+- [Value categories - cppreference.com](https://en.cppreference.com/w/cpp/language/value_category)
+- [rvalue 參考](https://openhome.cc/Gossip/CppGossip/RvalueReference.html)