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This article introduces the relevant knowledge of "mobile bit operation example explanation in java". In the operation process of actual cases, many people will encounter such difficulties. Next, let Xiaobian lead you to learn how to deal with these situations! I hope you can read carefully and learn something!

1. concept

Right shift operator, right shift is preceded by 1 or 0, num>> 1, equivalent to num divided by 2

>>> No sign right shift, yes in front of 0, ignore the sign bit, empty spaces are filled with 0

In addition, whether it is left or right shift 32 bits, equivalent to no move, or the original value.

In fact, when the Java virtual machine executes this code, it executes as follows:

5>>(n%32)---> Results

You have n = 32 here; so 5>> 32 is the result of 5>>(32%32)--> 5>> 0;

2. test code

public class Test{public Test(){System.out.println ("=========== Arithmetic Shift Right>======"); int i = 0xC 000000; System. out. println ("before shift: i ="+ i +"="+ Integer. toBinaryString (i)+"(B)"); i = i>> 28; System.out.println ("after shift: i ="+ i +"="+ Integer. toBinaryString (i)+"(B)"); System. out. println ("---------------------------------"); int j=0x0C000000; System.out.println ("before shift: j ="+ j +"="+ Integer. toBinaryString (j)+"(B)"); j = j>> 24; System. out. println ("after shift: j ="+ j +"="+ Integer. toBinaryString (j)+"(B)"); System. out. println ("\n "); System. out. println ("================= logical shift right>>======="); int m = 0xC000000; System. printout.("before shift: m ="+ m +"="+ Integer. toBinaryString (m)+"(B)"); m = m>> 28; System. out. println ("after shift: m ="+ m +"="+ Integer. toBinaryString (m)+"(B)"); System. out. println ("---------------------------------"); int n=0x0C000000; System.out.println ("before shift: n ="+ n +"="+ Integer. toBinaryString (n)+"(B)"); n = n>> 24; System. out. println ("after shift: n ="+ n +"="+ Integer. toBinaryString (n)+"(B)"); System. out. println ("\n "); System. out. println ("====================="); int a = 0xCC00000; System. printout.("before shift: a ="+ a +"="+ Integer. toBinaryString (a)+"(B)"); System. out. println ("Arithmetic shift right 32: a ="+(a>> 32)+"="+ Integer. toBinaryString (a>> 32)+"(B)"); System.out.println ("logical shift right 32: a ="+(a>>> 32)+"="+ Integer. toBinaryString (a>>> 32)+"(B)"); System.out.println ("Arithmetic shift right 64: a ="+(a>> 64)+"="+ Integer. toBinaryString (a>> 64)+"(B)"); System.out.println ("logical shift right 64: a ="+(a>>> 64)+"="+ Integer. toBinaryString (a>>> 64)+"(B)");} public static void main (String [] args){new Test ();}}

Run Results:

====================================

Before shift: i =-1073741824 = 110000000000000000000000 (B)

After shift: i =-4 = 11111111111111111111111111100 (B)

Before shift: j = 201326592 = 1100000000000000000 (B)

After shift: j = 12 = 1100 (B)

==============

Before shift: m =-1073741824 = 11000000000000000000000 (B)

After shift: m = 12 = 1100 (B)

Before shift: n = 201326592 = 110000000000000000 (B)

After shift: n = 12 = 1100 (B)

=====================

Before shift: a =-872415232 = 110011000000000000000 (B)

Arithmetic right shift 32: a =-872415232 = 1100110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

Logic shift right 32: a =-872415232 = 1100110000000000000000000 (B)

Arithmetic right shift 64: a =-872415232 = 1100110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

Logic shift right 64: a =-872415232 = 110011000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

3. Why isn't there an unsigned left shift?

You can think about this problem and you should be able to figure it out. (Note: None means none exists.)

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