什么是复制和交换习语？ - What is the copy-and-swap idiom?

问题：

What is this idiom and when should it be used? 这个习语是什么，何时应该使用？ Which problems does it solve? 它能够解决哪些问题？ Does the idiom change when C++11 is used? 使用C ++ 11时，习惯用法会改变吗？

Although it's been mentioned in many places, we didn't have any singular "what is it" question and answer, so here it is. 尽管在不少地方都提到过它，可是咱们没有任何奇异的“这是什么”的问题和答案，因此就在这里。 Here is a partial list of places where it was previously mentioned: 这是先前提到的地方的部分列表：

• What are your favorite C++ Coding Style idioms: Copy-swap 您最喜欢的C ++编码样式惯用法是什么：复制交换
• Copy constructor and = operator overload in C++: is a common function possible? 在C ++中复制构造函数和=运算符重载：是否可能使用通用函数？
• What is copy elision and how it optimizes copy-and-swap idiom 什么是复制省略及其如何优化复制和交换习惯
• C++: dynamically allocating an array of objects? C ++：动态分配对象数组？

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解决方案：

参考一： https://stackoom.com/question/Dl9r/什么是复制和交换习语
参考二： https://oldbug.net/q/Dl9r/What-is-the-copy-and-swap-idiom