Printing out selected items from an enum flag - c++

Question

I have the following enum (which later will grow larger!):
enum TrainingFilters {
NONE = 0,
GAUSS = 1,
SOBEL = 2,
FEATURE = 4
};
I have to print out string representation of the all possible combination. For now, a not-leangthy switch statement works fine, but if I add more items it will be disaster!
void Manager::setFilters(int filters)
{
QString what("Selected filters:");
switch (filters) {
case 0:
what.append(" NONE ");
break;
case 1:
what.append(" GAUSS ");
break;
case 1 | 2:
what.append(" GAUSS SOBEL ");
break;
case 2:
what.append(" SOBEL ");
break;
case 2 | 4:
what.append(" SOBEL FEATURE ");
break;
case 4:
what.append(" FEATURE ");
break;
case 1 | 4:
what.append(" GAUSS FEATURE ");
break;
case 1 | 2 | 4:
what.append(" GAUSS SOBEL FEATURE ");
break;
default:
qDebug() << "Invalid FILTERS enum received!";
return;
}
qDebug() << what;
mFilters = static_cast<TrainingFilters>(filters);
}
P.S: I have a few checkbox items in the user interface, and I should do some stuff according to the checked checkboxes. I use it like this:
var a, b,c;
cbGauss.checked ? a = 1 : a = 0;
cbSobel.checked ? b = 2 : b = 0;
cbFeat.checked ? c = 4 : c = 0;
cpManager.setFilters(a | b | c);
So my qustion is what is the best/easiest/smartest way to achieve this?

Answer 1

You could simply do
if (filters & 1)
what.append("GAUSS ");
if (filters & 2)
what.append("SOBEL ");
if (filters & 4)
what.append("FILTER ");
And so on. This way you can easily add new ones. Of course you have to check for zero and then add NONE.