java - 为什么3>>32等于3？

Question

这个问题已经有答案了:

Java right shift integer by 32 [duplicate] (2 个回答)

Is right shift undefined behavior if the count is larger than the width of the type? (2 个回答)

已关闭 4 年前。

why 3 right shift 32 is equal to 3 and not 0.

我在 NodeJs 和 Java 中得到了这些结果

• 3 >> 31 = 0
• 3 >> 32 = 3
• 3 >> 33 = 1
• 3 >> 34 = 0
• 3 >> 35 = 0

Answer 1

这是 Java 语言规范的一部分。右侧操作数被换行，使其始终位于 0 - bits 范围内，其中 bits 是左侧操作数的位数。由于您要移位 32 位整数，因此右侧操作数会包含在 0 到 31 之间。32 变为 0，33 变为 1 等。

请参阅Java language specification for shift operators :

If the promoted type of the left-hand operand is int, only the five lowest-order bits of the right-hand operand are used as the shift distance. It is as if the right-hand operand were subjected to a bitwise logical AND operator & (§15.22.1) with the mask value 0x1f (0b11111). The shift distance actually used is therefore always in the range 0 to 31, inclusive.