为什么Integer.MIN_VALUE的负数给出相同的值? [英] Why does the negative of Integer.MIN_VALUE give the same value?

问题描述

考虑以下Java代码.

Consider the below java code.

Integer value = Integer.MIN_VALUE;
System.out.println(value);

value = -value;
System.out.println(value);

输出

-2147483648
-2147483648

Integer.MIN_VALUE值的负值如何产生相同的值?

但是结果不能为2147483648，因为java中Integer的最大值为2147483647.

How the negative value of Integer.MIN_VALUE value results the same value?

However the result can't be 2147483648 because the maximum value of Integer in java is 2147483647.

但是想知道为什么-2147483648吗?内部正在发生哪种按位运算?

But want to know why -2147483648? What kind of bit-wise operations are happening internally?

推荐答案

内部发生了什么样的按位运算?

What kind of bit-wise operations are happening internally?

Java使用带符号的数字的二进制补语表示.因此，更改符号操作包括两个步骤:

Java uses two's complement representation of signed numbers. Therefore, the change of sign operation, consists of two steps:

1. 反转原始值的位，并且
2. 将1添加到结果中.

1. Inverting the bits of the original value, and
2. Adding 1 to the result.

2147483648的表示如下所示:

10000000000000000000000000000000

将其反转产生

01111111111111111111111111111111

添加1会使它再次成为相同的数字，即

Adding 1 makes it the same number again, i.e.

10000000000000000000000000000000

由于整数溢出.

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