Strings in enums?

[JaxDragon]

I was reading my C++ book, when I stumbled across enums. I understand them enough, although I cant figure out how to use a string as one of its values. Any help?

[Falco Girgis]

Well, think about what they are.

eNUMERATED types. Meaning what? Numbers. You can't do that. XD

[MarauderIIC]

...in C++. In some other languages you can. Dunno why it can't be done in C++ if you overload the == operator to use strcmp, or something, besides the fact that the language doesn't support it.

[trufun202]

Yeah, worst case you could always create a lookup. Take the value of the enum and use it as an index in the array of corresponding strings.

[JaxDragon]

Well, think about what they are.

eNUMERATED types. Meaning what? Numbers. You can't do that. XD

Lol...guess my book doesn't tell me that much. It requires a GyroVorbis(sold seperately). And i'll try trufun202's theory when I get to arrays.

If you're wondering "What crap book teaches about classes and enums before arrays?" Well, that book is C++ for dummies, All-in-one.

[programmerinprogress]

If you're wondering "What crap book teaches about classes and enums before arrays?" Well, that book is C++ for dummies, All-in-one.

I believe most books do, it's imperative that you know about constants and their uses before you move onto arrays, mainly because you tend to initialise static arrays using constants, and loops (mainly the for loop) usually rely on you to specify a maximum/minimum value, and constants help A LOT.

I'm surprised they actually covered strings before all of that, most books usually wait till further on to introduce that stuff, because the old style C-string is a pointer to a char and the newer C++ style string is an object of the string class, so those two topics(pointers and classes) are usually way further on in the books considering you need to know how to just program before you start messing around with memory or dip your feet into OOP...

Apologies, I went on a bit, I hope it all goes well

[Falco Girgis]

Coming from a C background, I do find that pretty weird.

Structs are like towards the end of the book.

[avansc]

http://elysianshadows.com/phpBB3/viewto ... art=999999

i dont know if you would call that using strings as enums, but its definitely lexical.

[MarauderIIC]

With enumerators, you can do this :)

Code: Select all

enum myEnumerator {
    SOMETHING_1,
    SOMETHING_2,
    NUM_SOMETHINGS
};

int array[NUM_SOMETHINGS];
for (int i = 0; i < NUM_SOMETHINGS; ++i) {
}

for (int i = SOMETHING_1; i < NUM_SOMETHINGS; ++i) {
}

cout << array[SOMETHING_1] << array[SOMETHING_2] << endl;
/*
But you cannot do cout << array[NUM_SOMETHINGS]
*/

[JaxDragon]

Ah thanks for the brief tutorial on enum arrays.

[MarauderIIC]

Well, enum arrays implies an array of enums. Rather you just use the enum to iterate through the array and declare the size of it, which is what my post exemplifies.

[Innerscope]

/*
But you cannot do cout << array[NUM_SOMETHINGS]
*/

I haven't used iostream.h in a while... but is this true? Can you not "cout" the last element of an array?
If not, then do you mean:

/*
But you cannot do cout << array[myEnumerator]
*/

Right?

[programmerinprogress]

look carefully, you can NEVER access the maximum value in an array (in the context you're referring to), but the compiler won't stop you because C++ deliberately has no bounds checking.

values you can access in an array go from 0 to (n-1) you access the nth element in an array with (n-1), trying to access an element with the index n would make you access the element after the last one, if that makes any sense.

const int MAX = 5 for example could be used in a for loop to iterate through elements 0 to (MAX-1), but you would never access element MAX, because you are infact accessing the (MAXth +1) element, which of course, doesn't exist

[Innerscope]

look carefully, you can NEVER access the maximum value in an array (in the context you're referring to), but the compiler won't stop you because C++ deliberately has no bounds checking.

Oh yea, I forgot that's how c++ handles arrays.

Another thing is that in Marauder's example he hasn't assigned any values to any of the elements. Is the default value, the smallest integer like -214*10^6? (i could be confusing languages again)

[MarauderIIC]

In C/C++, default values are garbage, IIRC. Behavior undefined, etc.

But you could assign that way, too. I was trying to show how you could access array members using enumerators and make your code all friendly, and if you didn't need friendly (loop), you could loop using one, as well.