为什么在C ++中没有基类？ [英] Why is there no base class in C++?

问题描述

快速问题：从设计的角度来看，为什么在C ++中没有母体的基类，通常对象在其他语言？

Quick question: from a design point of view, why is that, in C++, there is no mother-of-all base-class, what's usually object in other languages?

推荐答案

找到最终裁决此处。
简言之，它不传达任何语义。这将有一个成本。模板对容器更有用。

The definitive ruling is found here. In short, it doesn't convey any semantic meaning. It will have a cost. Templates are more useful for containers.

为什么C ++没有通用类Object？

• 我们不需要：通用编程在大多数情况下提供静态类型安全的替代品。

Why doesn't C++ have a universal class Object?

• We don't need one: generic programming provides statically type safe alternatives in most cases. Other cases are handled using multiple inheritance.

没有有用的通用类：真正的通用不带有自己的语义。

There is no useful universal class: a truly universal carries no semantics of its own.

一个通用类鼓励对类型和接口的粗略思考，并导致过多的运行时检查。

A "universal" class encourages sloppy thinking about types and interfaces and leads to excess run-time checking.

使用通用基类意味着cost：对象必须被堆分配为多态;这意味着存储器和访问成本。堆对象不自然地支持复制语义。堆对象不支持简单的范围行为（这使资源管理复杂化）。通用基类鼓励使用dynamic_cast和其他运行时检查。

Using a universal base class implies cost: Objects must be heap-allocated to be polymorphic; that implies memory and access cost. Heap objects don't naturally support copy semantics. Heap objects don't support simple scoped behavior (which complicates resource management). A universal base class encourages use of dynamic_cast and other run-time checking.

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