C-需要比较int的n个最低位是否相等 [英] C - Need to compare `n` lowest bits of an int for equality

问题描述

C-需要比较int的最低位n是否相等.

C - Need to compare n lowest bits of an int for equality.

即n = 4;

xxxx1001 == xxxx1001(x无关)

xxxx1001 == xxxx1001 (x is don't care)

即n = 2； xxxxxx01 == xxxxxx01

I.e. n = 2; xxxxxx01 == xxxxxx01

想不出不用面具就可以做到的好方法，=).

Can't think of a nice way to do it without using masks, =).

推荐答案

根据位数创建掩码:

int mask = (1 << bits) - 1;

然后使用它来比较值:

if ((a & mask) == (b & mask))

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