C ++中经常被误解的概念是什么？ [英] What are the often misunderstood concepts in C++?

问题描述

在c ++中经常被误解的概念是什么？

What are the often misunderstood concepts in c++?

推荐答案

C ++ 确实具有自动资源

That C++ does have automatic resource management.

（大多数声称C ++没有内存管理的人试图过多地使用new和delete，而没有意识到他们是否允许C ++管理资源

(Most people who claim that C++ does not have memory management try to use new and delete way too much, not realising that if they allowed C++ to manage the resource themselves, the task gets much easier).

示例：（使用虚构的API，因为我现在没有时间检查文档）

Example: (Made with a made up API because I do not have time to check the docs now)

// C++
void DoSomething()
{
  File file("/tmp/dosomething", "rb");
  ... do stuff with file...
  // file is automatically free'ed and closed.
}

// C#
public void DoSomething()
{
  File file = new File("/tmp/dosomething", "rb");
  ... do stuff with file...

  // file is NOT automatically closed.
  // What if the caller calls DoSomething() in a tight loop?
  // C# requires you to be aware of the implementation of the File class
  // and forces you to accommodate, thus voiding implementation-hiding
  // principles.
  // Approaches may include:
  // 1) Utilizing the IDisposable pattern.
  // 2) Utilizing try-finally guards, which quickly gets messy.
  // 3) The nagging doubt that you've forgotten something /somewhere/ in your
  //    1 million loc project.
  // 4) The realization that point #3 can not be fixed by fixing the File
  //    class.
}

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