<<和>>在C ++中 [英] << and >> in C++

问题描述

我不太明白这意味着什么...我只是从我非常非常非常基本的Python体验学习C ++ ...所以这可能是一个非常愚蠢的问题。我的问题是...说你有你的经典的Hello World程序，你有以下行：

I don't quite understand what this means...I'm just learning C++ from my very very very basic Python experience...and so this may be a very stupid question. My question is...say you have your classic "Hello World" program and you have the line:

cout<<"Hello World!"<<endl;

<意思是...因为我只是看着在C中使用输入，看到你会做一些像：

what does the << mean...because I was just looking at using input in C and saw that you'd do something like:

int i;
cin>>i;

我注意到它有>>而不是<我已经读过那些是按位移位...我并不完全明白这些是什么...但我认为这可能不同这里...帮助...提前感谢

and I noticed that it has >> instead of << and I've read that those are bitwise shifts...and I don't exactly understand what those are...but I think it might be different here...Help...Thanks in advance

推荐答案

在Python中，您可以实现 __ lshift __ 和 __ rshift __ 做任何你想要的。在C ++中，它是相同的 - 而经典的意思是按位右移和按位移左，你可以使它做任何你想要的。

In Python, you can implement __lshift__ and __rshift__ to do whatever you want. In C++, it is the same - while the classic meaning is bitwise shift right and bitwise shift left, you can make it do whatever you want.

这可能是一个在C ++中最明显的违反敏感的运算符重载，但这只是如何 std :: ostream 和 std :: istream 工作。对于所有的C ++爱好者（包括我自己），我为这个奇怪的选择操作符道歉。只是想想它是数据流入的方向（ cout 在中添加 foo >， cin>> foo 将 cin 放入 从一个新来的人，这真的没有意义，但喝的C ++ Kool Aid，你会 OH YEAH 。相信我。

This is probably one of the most blatant violations of "sensible" operator overloading in C++, but that is just how std::ostream and std::istream work. For all of the C++ lovers out there (myself included), I apologize for this strange choice of operators. Just think of it as the direction that the data flows in (cout << foo puts a foo in cout, cin >> foo puts cin in foo), smile and be happy. From a newcomer, it really doesn't make sense, but drink the C++ Kool Aid and you'll be OH YEAH about it. Trust me.

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