byte b; // ... int i = b & 0xff;
To get the effect of a 16-bit unsigned use char.
To get the effect of a 32-bit unsigned:
int i; // ... long l = i & 0xffffffffL;If you have an extensive amount of unsigned work to do, especially 64-bit unsigned, you might find the WBEM classes useful.
Here is haw to handle unsigned short:
// combining two unsigned shorts into an unsigned int. short ush = 4; short usl = 9999; int ucombined = ( ush & 0xffff ) << 16 | ( usl & 0xffff );
For 64-bit unsigned, consider that addition and subtraction give you the same results whether you consider the operands signed or unsigned. When you multiply two unsigned 64-bit operands together you get a 128-bit result which won’t fit in a long anyway, so 64-bit unsigned multiply is not useful. To implement an unsigned 64-bit division, you could handle it 32 bits as a time, much the way you handled decimal division in grade 4. Check the signs first, if they are 0 just use ordinary division.
You could store a signed or unsigned number in byte, char, int or long.
Sometimes you get the same result in terms of bits whether you treat quantities as signed or unsigned.
|Does Signed/Unsigned Matter?|
|< <= > >=||comparison|
|& | ~ !||bitwise|
|>>> >> <<||shift|
For large unsigned numbers, look into BigInteger and a BigDecimal.
Java’s Integer.toString interprets the value as unsigned. To display unsigned longs, use Long.toHexString. Writing a base 10 unsigned converter would be a challenge. You also might find com.mindprod.common11.ST.toLZHexString and com.mindprod.common11.ST.toHexString might be useful.
Working with a mixture of constants and bytes, it is easy to trip up when int constants don’t sign extend and (byte) constants do. Consider this example:
available on the web at:
optional Replicator mirror
Please email your feedback for publication, letters to the editor, errors, omissions, typos, formatting errors, ambiguities, unclear wording, broken/redirected link reports, suggestions to improve this page or comments to Roedy Green : . If you want your message, your name or email kept confidential, not considered for public posting, please explicitly specify that. Unless you state otherwise, I will treat your message as a letter to the editor that I may or may not publish in the feedback section. After that, it will be too late to retract it. If you disagree with something I said, especially when sending an ad-hominem attack, a rant composed mainly of obscenities or a death threat, please quote the offending passage and cite the web page where you found it, tell me why you think it is wrong, and, if possible, provide some supporting evidence. I can’t very well fix erroneous or ambiguous text if I can’t find it.
Your face IP:[22.214.171.124]
|Feedback||You are visitor number 92,001.|