C语言 如何比较C中的两个位值？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/7479309/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to compare two bit values in C?
提问by thomascirca
I've been dabbling around a bit with C and I find that being able to directly manipulate bits is fascinating and powerful (and dangerous I suppose). I was curious as to what the best way would be to compare different bits in C would be. For instance, the number 15 is represented in binary as:
我一直在尝试使用 C 语言，我发现能够直接操作位是令人着迷和强大的（我想也是危险的）。我很好奇在 C 中比较不同位的最佳方法是什么。例如，数字 15 以二进制表示为：
00001111
And the number 13 is represented as:
数字 13 表示为：
00001101
How would you compare what bits are different without counting them? It would be easy to use shifts to determine that 15 contains 4 1s and 13 contains 3 1s, but how would you output the difference between the two (ex that the 2^1 spot is different between the two)? I just can't think of an easy way to do this. Any pointers would be much appreciated!
如果不计算它们，您将如何比较哪些位不同？使用移位来确定 15 包含 4 个 1 并且 13 包含 3 个 1 很容易，但是您将如何输出两者之间的差异（例如，两者之间的 2^1 点不同）？我只是想不出一个简单的方法来做到这一点。任何指针将不胜感激！
EDIT: I should have clarified that I know XOR is the right way to go about this problem, but I had an issue with implementation. I guess my issue was comparing one bit at a time (and not generating the difference per say). The solution I came up with is:
编辑：我应该澄清一下，我知道 XOR 是解决这个问题的正确方法，但我在实现方面遇到了问题。我想我的问题是一次比较一点（而不是产生差异）。我想出的解决方案是：
void compare(int vector1, int vector2) {
int count = 0;
unsigned int xor = vector1 ^ vector2;
while (count < bit_length) {
if (xor % 2 == 1) { //would indicicate a difference
printf("%d ", count);
}
xor >>= 1;
count++;
}
}
回答by Mateen Ulhaq
Use bitwise operations:
使用按位运算：
c = a ^ b ;
00000010b = 00001111b ^ 00001101b;
What ^, or XOR, does is:
什么^，或XOR，做的是：
0 ^ 0 = 0
1 ^ 0 = 1
0 ^ 1 = 1
1 ^ 1 = 0
One way of thinking about it would be:
一种思考方式是：
If the two operands (
aandb) are different, the result is1.
If they are equal, the result is0.
如果两个操作数 (
a和b) 不同，则结果为1。
如果它们相等，则结果为0。
