怎麼理解 `auto var = [&]() { /* things to do */ }`？

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struct Fuck
{
int shit;
int bitch;

Fuck(int _shit, int _bitch)
:shit(_shit), bitch(_bitch)
{
}

void operator()()
{
cin &>&> shit &>&> bitch;
}
};

int main()
{
int shit, bitch;
Fuck var;
var(shit, bitch);
cout &<&< shit &<&< bitch; } ////////////////////////////////////////////// int main() { int shit, bitch; auto var = [](){ cin &>&> shit &>&> bitch;};
var();
cout &<&< shit &<&< bitch; }

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看過一篇不錯的講解C++11 lambda的博客：

C++11 - Lambda Closures, the Definitive Guide

C++11/14 Rocks（http://cpprocks.com/books/）這本小書（clang版只有180頁）比較系統地介紹了C++11中的新特性，在講lambda時，有這麼一句話：

In fact, internally lambdas are implemented as classes with operator().

...

The compiler will generate the appropriate function object and pass an instance of it in place of the lambda expression.

至於這裡的auto，也是C++11中新增的type inference特性（auto、decltype、declval、……）。因為完整地寫出一個函數的原型是一件讓人不爽的事情，所以這裡就用auto，讓編譯器從初始化表達式自動推導出var的靜態類型了（如果不嫌麻煩，可以自己std::function&<...&>）。

其實，lambda、closure（閉包）這些概念我是在Python中接觸到的。哈哈。

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Lambda functions (since C++11)

a comma-separated list of zero or more captures, see below.

A list of symbols can be passed as follows:

• [a,b] where a is captured by value and b is captured by reference.
• [this] captures the this pointer by value
• [] captures all automatic variables mentioned in the body of the lambda by reference
  
• [=] captures all automatic variables mentioned in the body of the lambda by value
• [] captures nothing

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lambda么么噠~ 類似C#中() =&> { … }

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A lambda expression is essentially a class, a constructor, and a function call operator.

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lambda是一個比匿名函數強大得多的匿名函數類型。

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lambda,拿到當前scope中的所有變數。

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入

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C++ Primer中文版第五版 P506

說的比較詳細吧~

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