我需要使用Bit运算符比较两个整数。 我遇到了一个问题,我必须比较两个整数而不使用比较运算符。使用位运算符会有所帮助。但是如何?
I need to compare two integer using Bit operator. I faced a problem where I have to compare two integers without using comparison operator.Using bit operator would help.But how?
让我们说 a = 4; b = 5;
Lets say a = 4; b = 5;
我们必须显示a不等于b。 但是,我想进一步扩展它,比方说,我们将显示哪个更大。这里b更大..
We have to show a is not equal to b. But,I would like to extend it further ,say,we will show which is greater.Here b is greater..
推荐答案至少需要与0进行比较,从概念上讲,这就是CPU所做的比较。例如
You need at least comparison to 0 and notionally this is what the CPU does for a comparison. e.g.
等于可以建模为 ^ ,因为这些位必须相同才能返回0
Equals can be modelled as ^ as the bits have to be the same to return 0
(a ^ b) == 0如果这是 C 你可以放弃 == 0 ,因为这可以隐含
if this was C you could drop the == 0 as this can be implied with
!(a ^ b)但是在Java中你不能将 int 转换为 boolean 而不是至少一些比较。
but in Java you can't convert an int to a boolean without at least some comparison.
为了比较,你通常做一个减法,虽然一个处理溢出。
For comparison you usually do a subtraction, though one which handles overflows.
(long) a - b > 0 // same as a > b减法与添加负数相同且负数与~x + 1相同所以你可以做
subtraction is the same as adding a negative and negative is the same as ~x+1 so you can do
(long) a + ~ (long) b + 1 > 0放弃 +1 你可以将此更改为
(long) a + ~ (long) b >= 0 // same as a > b你可以实现 + 作为一个系列使用>> << & | 和 ^ 但我不会对你造成这种情况。
You could implement + as a series of bit by bit operations with >> << & | and ^ but I wouldn't inflict that on you.
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使用位运算符比较两个整数
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