循环通过C位 [英] Looping through Bits C

问题描述

我试图遍历无符号字符的位，但是我不确定从哪里开始，最终，我将对这些位执行其他按位运算，例如〜和xor..etc.

I'm trying to loop through the bits of an unsigned char, but I'm not sure where to start, eventually, I'll perform other bitwise operating on the bits, such as ~ and xor..etc.

推荐答案

可以通过以下几种方法进行位循环:

Looping over bits can be done in several ways:

• 当您移动值并根据枚举位的顺序测试初始或最终位时，您可以进行破坏性循环，或者
• 当您使用按位AND并通过左移1产生的单个 mask 来测试数字时，可以执行非破坏性循环.

• You can do a destructive loop, when you shift the value, and test the initial or the final bit, depending on the order in which you would like to enumerate bits, or
• You can do a non-destructive loop, when you use bitwise AND to test the number with a single-bit mask, produced by left-shifting 1.

以下是第一种方法的示例:

Here is an example of the first approach:

unsigned int bits = ...;
while (bits) {
    if (bits & 1) {
        // Current bit is set to 1
    } else {
        // Current bit is set to 0
    }
    bits >>= 1;
}

如果要在达到零后继续使用位，请另作一个计数器.

If you want to continue working with bits after you reach zero, make a separate counter.

以下是第二种方法的示例:

Here is an example of the second approach:

unsigned int bits = ...;
for (int pos = 0 ; pos != 16 ; pos++) {
    if (bits & (1 << pos)) {
        // Current bit is set to 1
    } else {
        // Current bit is set to 0
    }
}

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