这个

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这个问题在这里已有答案：

• What are bitwise shift (bit-shift) operators and how do they work? 8 answers
• 什么是按位移位（位移）运算符以及它们如何工作？ 8个答案

I am working on a simple project in C where I encountered this statement in one of the tutorials.

我正在使用C中的一个简单项目，我在其中一个教程中遇到了这个语句。

int i = 1 << 2 ;   

What does this statement actually do?

这个陈述实际上做了什么？

4 个解决方案

#1

This is also called the shift operator. It will shift de bits n positions to the left. Shifting the bits by one positions is the same as multiplying or dividing by 2.

这也称为移位运算符。它会将位n位置向左移位。将位移位一个位置与乘以或除以2相同。

#2

It is a left-shift operator.

这是一个左移运营商。

It applies on the bit representation of 1 and shift it's bits to left by 2 position.

它适用于1的位表示，并将其位向左移位2位。

#3

<< is a binary Left Shift operator. The left operands value is shifted left by the number of bits specified by the right operand. and 0 are padded in the right. So the binary of 1 i.e, 1 is shifted left 2 places and becomes 100 which is 4 in decimal number system. So i is assigned 4.

< <是二元左移运算符。左操作数值向左移动右操作数指定的位数。和0填充在右边。因此，1，1的二进制数向左移位2位，变为100，十进制数系统为4。所以我被分配了4。< p>

Here is a quick tutorial that explains bitwise operations

这是一个解释按位操作的快速教程

#4

Shift left is a bitwise operation. Look here: Bitwise operations in C wiki

左移是一个按位操作。看这里：C维基中的按位运算