Java supports two type of right shift operator. The>> operator is a signed right shift operator and >>> is an unsigned right shift operator. The left operands value is moved right by the number of bits specified by the right operand.
The signed right shift operator '>>' uses the sign bit to fill the trailing positions. For example, if the number is positive then 0 will be used to fill the trailing positions and if the number is negative then 1 will be used to fill the trailing positions.
Assume if a = 60 and b = -60; now in binary format, they will be as follows −
a = 0000 0000 0000 0000 0000 0000 0011 1100 b = 1111 1111 1111 1111 1111 1111 1100 0100
In Java, negative numbers are stored as 2's complement.
Thus a >> 1 = 0000 0000 0000 0000 0000 0000 0001 1110 And b >> 1 = 1111 1111 1111 1111 1111 1111 1110 0010
The unsigned right shift operator '>>' do not use the sign bit to fill the trailing positions. It always fills the trailing positions by 0s.
Thus a >>> 1 = 0000 0000 0000 0000 0000 0000 0001 1110 And b >>> 1 = 0111 1111 1111 1111 1111 1111 1110 0010
public class Tester { public static void main(String[] args) { int a = 60; int b = -60; int c = 0; System.out.println("60 = " + Integer.toBinaryString(a)); System.out.println("-60 = " + Integer.toBinaryString(b)); //signed shift c = a >> 1; System.out.println("60 >> 1 = " + Integer.toBinaryString(c)); //unsigned shift c = a >>> 1; System.out.println("60 >>> 1 = " + Integer.toBinaryString(c) ); c = b >> 1; System.out.println("-60 >> 1 = " + Integer.toBinaryString(c) ); c = b >>> 1; System.out.println("-60 >>> 1 = " + Integer.toBinaryString(c)); } }
60 = 111100 -60 = 11111111111111111111111111000100 60 >> 1 = 11110 60 >>> 1 = 11110 -60 >> 1 = 11111111111111111111111111100010 -60 >>> 1 = 1111111111111111111111111100010