enumerations

[scooter]

say I have an enumeration:

enum Ecolor {eRed, eGreen, eBlue, eBrown, eNumColors};

and a variable:

Ecolor eCurrentColor = eGreen;

How can I increment or decrement eCurrentColor?

(since I can't just do eCurrentColor++ )

thanks

[Thomas Tutone]

Re: enumerations

On Feb 7, 10:12 am, scooter <inva...@invali d.netwrote:

say I have an enumeration:
>
enum Ecolor {eRed, eGreen, eBlue, eBrown, eNumColors};
>
and a variable:
>
Ecolor eCurrentColor = eGreen;
>
How can I increment or decrement eCurrentColor?
>
(since I can't just do eCurrentColor++ )

Create your own operator++ that takes an Ecolor:

Ecolor& operator++(Ecol or& color)
{
// insert your code here to change color appropriately
return color;
}

Ecolor operator++(Ecol or& color, int)
{
Ecolor temp = color;
++color;
return temp;
}

Best regards,

Tom

[Greg Herlihy]

Re: enumerations

On 2/7/07 7:12 AM, in article mtqjs2hrionk291 okn8ub8al87hdqr u7j2@4ax.com,
"scooter" <invalid@invali d.netwrote:

say I have an enumeration:
>
enum Ecolor {eRed, eGreen, eBlue, eBrown, eNumColors};
>
and a variable:
>
Ecolor eCurrentColor = eGreen;
>
How can I increment or decrement eCurrentColor?
>
(since I can't just do eCurrentColor++ )

Sure you can - assuming a suitable overloaded operator exists:

Ecolor operator++( Ecolor e, int)
{
return Ecolor(e + 1);
}

int main()
{
Ecolor eCurrentColor = eGreen;

eCurrentColor++ ; // OK
...
}

Of course it's a unclear what should happen when the last enumerated type is
incremented (should incrementing have no effect or should it "wrap around"
to the first enum?) Generally, a program should treat enums as distinct
categories of a type rather than as a range of numerical values.

Greg