auto c++ 关键字有什么作用? [英] What does the auto c++ keyword do?

问题描述

我最近遇到了 C++ 中的关键字 auto.

I recently came accross the keyword auto in c++.

在代码中:

auto maxIterator = std::max_element(&spec[0], &spec[sampleSize]);
float maxVol = *maxIterator;

// Normalize
if (maxVol != 0)
  std::transform(&spec[0], &spec[sampleSize], &spec[0], [maxVol] (float dB) -> float { return dB / maxVol; });

这与对音频流运行频率分析有关.来自网站:http://katyscode.wordpress.com/2013/01/16/cutting-your-teeth-on-fmod-part-4-frequency-analysis-graphic-均衡器节拍检测和 bpm 估计/

This is to do with running a frequency analysis on a audio stream. From the website: http://katyscode.wordpress.com/2013/01/16/cutting-your-teeth-on-fmod-part-4-frequency-analysis-graphic-equalizer-beat-detection-and-bpm-estimation/

我已经搜索了论坛，但它说该关键字没有用.有人可以在这里解释一下它的用法吗.

I have searched the forums but It says that there is no use for the keyword. Could someone please explain the use of it here.

我对 C++ 很陌生，所以请尽量不要让答案太复杂.非常感谢大家.

I am quite new to c++ so please try not to make the answers too complicated. Thanks so much all.

自动使 maxIterator 也成为指针吗?

Did auto make maxIterator a pointer also?

推荐答案

在 C++11 中，关键字 auto 从其初始化表达式推导出声明变量的类型.因此，在您的代码中，它推导出 maxIterator 的类型.

In C++11, the keyword auto deduces the type of declared variable from its initialization expression. Hence, in your code it deduces type of maxIterator.

有关 auto 的更多信息，请查看此处

For more information on auto look here

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