什麼是複製和交換習語？ - What is the copy-and-swap idiom?

問題：

What is this idiom and when should it be used? 這個習語是什麼，何時應該使用？ Which problems does it solve? 它能夠解決哪些問題？ Does the idiom change when C++11 is used? 使用C ++ 11時，習慣用法會改變嗎？

Although it's been mentioned in many places, we didn't have any singular "what is it" question and answer, so here it is. 儘管在不少地方都提到過它，可是咱們沒有任何奇異的「這是什麼」的問題和答案，因此就在這裏。 Here is a partial list of places where it was previously mentioned: 這是先前提到的地方的部分列表：

• What are your favorite C++ Coding Style idioms: Copy-swap 您最喜歡的C ++編碼樣式慣用法是什麼：複製交換
• Copy constructor and = operator overload in C++: is a common function possible? 在C ++中複製構造函數和=運算符重載：是否可能使用通用函數？
• What is copy elision and how it optimizes copy-and-swap idiom 什麼是複製省略及其如何優化複製和交換習慣
• C++: dynamically allocating an array of objects? C ++：動態分配對象數組？

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解決方案：

參考一： https://stackoom.com/question/Dl9r/什麼是複製和交換習語
參考二： https://oldbug.net/q/Dl9r/What-is-the-copy-and-swap-idiom