Hi
how can i declare an unsigned short value in Java?
Thank you
+7
A:
You can't, really. Java doesn't have any unsigned data types, except char.
Admittedly you could use char - it's a 16-bit unsigned type - but that would be horrible, as char is clearly meant to be for text.
Jon Skeet
2009-12-03 17:19:10
Another great answer. Jon Skeet, you are my hero.
Yada
2009-12-03 18:00:52
+1
A:
Java does not have unsigned types. What do you need it for?
Java does have the 'byte' data type, however.
CBFraser
2009-12-03 17:19:11
i would like to build a multi-dimensional array with for example 10000*10000 entries of short numbers... thats why i thought of unsigned shorts, for allocating less memory
maiky
2009-12-04 00:06:20
Makes sense, @maiky. Also, if you're worried about memory, you could probably lift the tricks from sparse matrices if you anticipate a lot of entries in your array will be zero.
CBFraser
2009-12-04 02:42:51
A:
Yep no such thing if you want to use the value in code vs. bit operations.
Xepoch
2009-12-03 17:19:15
+3
A:
You can use a char, as it is an unsigned 16 bit value (though technically it is a unicode character so could potnetially change to be a 24 bit value in the future)... the other alternative is to use an int and make sure it is within range.
Don't use a char - use an int :-)
And here is a link discussing Java and the lack of unsigned.
TofuBeer
2009-12-03 17:19:44
char is defined to be 16 bits, not a Unicode character (whatever that means), always and forever. If char changed to 24 bits, it would no longer be Java.
Ken
2009-12-03 18:00:31
I don't think it'll ever change either. The reason why 16 bits is to support unicode (from the JLS: "The Java platform tracks the Unicode specification as it evolves." and "The Unicode standard was originally designed as a fixed-width 16-bit character encoding") and from java.lang.Character: "The methods that only accept a char value cannot support supplementary characters" - so origianlly char was 16 bit because that was how wide unicode was. Now unicode is larger and char can no longer represent all unicode characters.
TofuBeer
2009-12-03 20:02:46
A:
You can code yourself up a ShortUnsigned class and define methods for those operators you want. You won't be able to overload + and - and the others on them, nor have implicit type conversion with other primitive or numeric object types, alas.
Like some of the other answerers, I wonder why you have this pressing need for unsigned short that no other data type will fill.
Carl Smotricz
2009-12-03 17:56:10
A:
If you really need a value with exactly 16 bits:
Solution 1: Use the available signed short and stop worrying about the sign, unless you need to do comparison (<, <=, >, >=) or division (/, %, >>) operations. See this answer for how to handle signed numbers as if they were unsigned.
Solution 2 (where solution 1 doesn't apply): Use the lower 16 bits of int and remove the higher bits with & 0xffff where necessary.
starblue
2009-12-03 18:20:39