为什么编译器提供默认的复制构造函数

Why compiler provides default copy constructor(为什么编译器提供默认的复制构造函数)

问题描述

我想知道为什么编译器提供默认的复制构造函数.这个想法背后的策略是什么.

I wanted to know Why compiler provides default copy constructor..Whats the strategy behind that idea.

提前致谢.

推荐答案

来自一个相关(但不相同)的问题 - 为什么 C++ 编译器不定义 operator== 和 operator!=?:

From a related (but not same) question - Why don't C++ compilers define operator== and operator!=?:

Stroustrup 在The Design and Evolution of C++"(第 11.4.1 节 - 复制控制)中谈到了默认的复制构造函数:

Stroustrup said this about the default copy constructor in "The Design and Evolution of C++" (Section 11.4.1 - Control of Copying):

我个人认为很遗憾复制操作是默认定义的，并且我禁止复制我的许多类的对象.但是，C++ 继承了 C 的默认赋值和复制构造函数，并且经常使用.

I personally consider it unfortunate that copy operations are defined by default and I prohibit copying of objects of many of my classes. However, C++ inherited its default assignment and copy constructors from C, and they are frequently used.

所以答案是，Stroustrup 不情愿地包含它是为了与 C 向后兼容(可能是大多数 C++ 缺陷的原因，但也可能是 C++ 流行的主要原因).

So the answer is that it was included reluctantly by Stroustrup for backwards compatibility with C (probably the cause of most of C++'s warts, but also probably the primary reason for C++'s popularity).

出于我自己的目的，在我的 IDE 中，我用于新类的代码段包含私有赋值运算符和复制构造函数的声明，因此当我生成一个新类时，我不会得到默认的赋值和复制操作 - 我必须明确如果我希望编译器能够为我生成这些操作，请从 private: 部分删除这些操作的声明.

For my own purposes, in my IDE the snippet I use for new classes contains declarations for a private assignment operator and copy constructor so that when I gen up a new class I get no default assignment and copy operations - I have to explicitly remove the declaration of those operations from the private: section if I want the compiler to be able to generate them for me.

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