Does the first enumerator have default value of 0 like in C++?

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iherage - 15 May 2006 12:54 GMT

In C++, by default, the first enumerator has a value of 0, and each
successive enumerator is one larger than the value of the previous one,
unless you explicitly specify a value for a particular enumerator.

What about in Java ( JDK 5.0)? Can I assign a value to the particular
enumerator?
I have googled for it and found nothing. Does anyone know?
Thank you.

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Thomas Hawtin - 15 May 2006 12:22 GMT

> In C++, by default, the first enumerator has a value of 0, and each
> successive enumerator is one larger than the value of the previous one,
[quoted text clipped - 3 lines]
> enumerator?
> I have googled for it and found nothing. Does anyone know?

http://download.java.net/jdk6/docs/api/java/lang/Enum.html#ordinal()

You can also, of course, add methods to your enum to return whatever
value you like.

Tom Hawtin

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Unemployed English Java programmer
http://jroller.com/page/tackline/

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Chris Uppal - 15 May 2006 13:23 GMT

> http://download.java.net/jdk6/docs/api/java/lang/Enum.html#ordinal()

And pay particular attention to the sentence:

"Most programmers will have no use for this method."

-- chris

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dingbat@codesmiths.com - 15 May 2006 14:03 GMT

> In C++, by default, the first enumerator has a value of 0, and each
> successive enumerator is one larger than the value of the previous one,
> unless you explicitly specify a value for a particular enumerator.

> What about in Java ( JDK 5.0)?

Simple. You write code like that in my projects and I'll break your
fingers.

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Jeffrey Schwab - 15 May 2006 14:05 GMT

>> In C++, by default, the first enumerator has a value of 0, and each
>> successive enumerator is one larger than the value of the previous one,
[quoted text clipped - 4 lines]
> Simple. You write code like that in my projects and I'll break your
> fingers.

Seems a little harsh. Problems at home?

Seriously, you have a beef with sequences of named, consecutive integers?

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Chris Uppal - 15 May 2006 14:39 GMT

> Seriously, you have a beef with sequences of named, consecutive integers?

I doubt it, but where is the connection between integers and instances of
(subtypes of) java.lang.Enum ?

Unlike the case in C and C++, Java's enums are not fancy syntax for a list of
integers -- they are /objects/. They can have integers /associated/ with them,
sure. And floats. And Strings...

I suspect the OP hasn't realised this, and that dingbat's post was a gentle
hint to the same effect ;-)

-- chris

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Jeffrey Schwab - 15 May 2006 14:47 GMT

>> Seriously, you have a beef with sequences of named, consecutive integers?
>
[quoted text clipped - 7 lines]
> I suspect the OP hasn't realised this, and that dingbat's post was a gentle
> hint to the same effect ;-)

That makes sense. It also explains the exasperation. Thanks.

I have not had much occasion to use Java Enums yet, but they do look
promising. Just for the record, though:

    - C++ enums are first-class types. They're not just integers.
    This is in contrast to C.

    - Mr. Bat's issue may have been with the implicit default value
    of zero. It seems appropriate, though, since several other
    Java types' default values are also zero.

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Roedy Green - 20 May 2006 19:26 GMT

>What about in Java ( JDK 5.0)? Can I assign a value to the particular
>enumerator?
> I have googled for it and found nothing. Does anyone know?
> Thank you.

A Java automatically assigns integers starting at 0. You of course are
free to invent some other method of your own that assigns something
else, e.g. a non-consecutive it, a char, a short string, a
description...

See http://mindprod.com/jgloss/enum.html

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Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

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Does the first enumerator have default value of 0 like in C++?

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