Shift operators in Java

Keep in mind that all the moving digits are in the complement, so first convert the decimal integer to the complement and then the shift operation.

Shift operation also pay attention to the type of constraints, such as int, moving range is 0-31 bits, so the complement can only see the last five digits, this is a valid number, long moving range is 0-63, so the complement can only see the last six bits.

move the operator right .

Left shift operator (<<): Both the signed number and the unsigned number are low 0.

Signed right shift operator (>>): With symbol extension, 0 for positive high, and 1 for negative high.

Unsigned tips : Shift Assignment

I >>= 10;

The value of I to the right of 10 bits is then assigned to I. Equivalent to: i = i >> 10;.

Shift pretreatment

When a char, byte, Shor type is shifted, it is automatically converted to the int type and then shifted. Since the int type is only 32 bits, when the shift occurs:

I << 127;

, the I of the int type certainly does not move 127 bits to the left, but only the left 32 bits (= 2^5,127 = 1111 1111). Therefore, when the int type shifts, the shift number is only 5 bits low. Similarly, when a long is shifted, the shift number is only 6 bits low.

Instance:

public class Main {public static void main(String[] args) {System.out.println(1 << -2);System.out.println(1 << 30);System.out.println(1L << -2);System.out.println(1L << 62);}}

1073741824107374182446116860184273879044611686018427387904

int is a 32-bit, long is 64-bit, moving negative digits or exceeding the number of digits should take the remainder to 0~31, 0~63.

Shift operators in Java