结构与类的表现 [英] Performances of Structs vs Classes

问题描述

我想知道是否有使用 g++ -O3 选项对 C++ 中的类和 C 风格结构进行性能比较.是否有任何基准或比较.我一直认为 C++ 类比结构更重，可能也更慢(编译时间对我来说不是很重要，运行时间更重要).我将要实现一个 B 树，为了性能，我应该用类还是用结构来实现它.

I wonder if there are performance comparisons of classes and C style structs in C++ with g++ -O3 option. Is there any benchmark or comparison about this. I've always thought C++ classes as heavier and possibly slower as well than the structs (compile time isn't very important for me, run time is more crucial). I'm going to implement a B-tree, should I implement it with classes or with structs for the sake of performance.

推荐答案

在运行时级别，C++ 中的结构和类之间没有区别.因此，无论您在代码中使用 struct A 还是 class A，都不会产生任何性能差异.

On runtime level there is no difference between structs and classes in C++ at all. So it doesn't make any performance difference whether you use struct A or class A in your code.

其他的事情是使用一些特性——比如构造函数、析构函数和虚函数——可能会有一些性能损失(但如果你使用它们，你可能仍然需要它们).但是你可以同样成功地在你的类或结构中使用它们.

Other thing, is using some features -- like, constructors, destructors and virtual functions, -- could have some performance penalties (but if you use them you probably need them anyway). But you can with equal success use them both inside your class or struct.

在本文档中，您可以阅读其他C++ 与性能相关的细微之处.

In this document you can read about other performance-related subtleties of C++.

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