Azazel <[EMAIL PROTECTED]> writes:
> I'm out of patience and ideas. Can somebody tell me why the following code gives the
> output it does. The programme should take a given long number, shift it 8 bits each
> way (signed and unsigned), and print all the different bit-patterns. As I see it,
>one
> of two things is happening.
>
> 1. There's a bug in the JDK and bitwise operators don't work properly, which
> seems unlikely.
> 2. The dprint function is not printing the actual bit-strings but I can't see why.
>
> <code>
> public class pubtest
> {
> public static void main(String args[])
> {
> long n;
>
> n=0xf0f0f0f0;
>
> System.out.print("n:\t");
> dprint(n);
> System.out.print("n>>8:\t");
> dprint(n>>8);
> System.out.print("n>>>8:\t");
> dprint(n>>>8);
> System.out.print("n<<8:\t");
> dprint(n<<8);
>
> n=0x0f0f0f0f;
>
> System.out.print("n:\t");
> dprint(n);
> System.out.print("n>>8:\t");
> dprint(n>>8);
> System.out.print("n>>>8:\t");
> dprint(n>>>8);
> System.out.print("n<<8:\t");
> dprint(n<<8);
> }
>
> private static long dprint(long l)
> {
> for(int i=1<<31; i!=0; i>>>=1)
> System.err.print((l&i)!=0?"1":"0");
> System.err.print("\n");
>
> return l;
> }
> }
> </code>
>
long is 64 bit
int is 32 bit
If you want to use long:
Change n=0xf0f0f0f0 to n=0xf0f0f0f0L,
n=0x0f0f0f0f to n=0x0f0f0f0fL
and
for(int i=1<<31; i!=0; i>>>=1)
System.err.print((l&i)!=0?"1":"0");
to
for(long i=1L<<63; i!=0; i>>>=1) // Note the L behind the 1
System.err.print((l&i)!=0?"1":"0");
If you want to use int:
Just change long n to int n.
By the way, you can use Integer.toBinaryString(int)/Long.toBinaryString(long)
to display int/longs in base 2 format.
Jürgen
--
Juergen Kreileder, Universitaet Dortmund, Lehrstuhl Informatik V
Baroper Strasse 301, D-44221 Dortmund, Germany
Phone: ++49 231/755-5806, Fax: ++49 231/755-5802
