dato datuashvili dato datuashvili - 3 months ago 19
Java Question

Reverse bits in number

For example, I have the binary number 1011 which is equal to decimal 11. I want the reverse bit's location such that it become 1101, which is decimal 13. Here is code:

import java.util.*;
public class bits {
public static void main(String[] args) {
Scanner scnr=new Scanner(System.in);
System.out.println("enter x:");
int x=scnr.nextInt();
int b=0;
while (x!=0){
b|=( x &1);
x>>=1;
b<<=1;
}
System.out.println(b);
}
}


But when I enter x 11 then it prints 26. What is the mistake?

Answer

You are shifting b one time too many. Do the shift first (so that the first time, when b == 0, it has no effect):

while (x!=0){
  b<<=1;
  b|=( x &1);
  x>>=1;
}
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