左移 [英] Bit shifting left

问题描述

假设我想将i左移两次，并将值存储在f中.

Let's say I want to bit shift i twice to the left and store the value in f.

f = i << 2;

那是正确的吗?我该如何在C/C ++中做到这一点?

Is that correct? How exactly do I do this in C/C++?

推荐答案

是.

f = i << 2

在许多位旋转操作中，移位非常有用.

Shifts are useful in a number of bit twiddling operations.

这曾经是将数字乘以4的好方法.但是，如今，优化编译器往往会为您解决这一问题.

This used to be a great way to multiply a number by four. However, these days, optimizing compilers tend to take care of that for you.

请记住，最左边的两个位被丢弃了.

Keep in mind that the two leftmost bits are discarded.

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