How to get no of items defined in enum ?

[ankit thakar]

Hello All,

I got one situation in which i want total no. of items defined in enum.
for e.g.

enum temp
{ A, B, C }

Now I want it should return value 3.
I googled it how to do it but everybody did like patch work either defining one extra last element in enum or by subtracting the value from LAST - FIRST + 1 .

But above mentioned solution is not perfect.

Does anybody have an idea how to do this ?

Thanks in advance...

[Devopia53]

@ankit-thakar

Hi.

Yes. You can use the Qt's Meta-Object System(a called QMetaEnum). You can also use QMetaEnum::fromType() to get the QMetaEnum.

Something like this:

  class MyClass : public QObject
  {
      Q_OBJECT

  public:
      MyClass(QObject *parent = 0);
      ~MyClass();

      enum Priority { High, Low, VeryHigh, VeryLow };
      Q_ENUM(Priority)
  };

[...]
#include <QMetaEnum>

QMetaEnum   en = QMetaEnum::fromType<Priority>();
qDebug() << en.name() << en.keyCount();
[...]

[kshegunov]

@ankit-thakar

I don't know why you don't like it, but the usual way is to add a dummy at the end.

@Devopia53

My issue with that solution is that you're getting the information at runtime, instead of at compile time. There is increased chance of errors and there isn't really a need to inquire the meta object system in this case.