Hi dakensta,

I am experiencing one more problem releated to aggregate type errors.

The code is as follows

#include<iostream>
using namespace std;
class xyz
{
public:
typedef enum {a=0,b,c,d} control;
};
int main()
{
if( xyz::control::a == 0)
{
}
return 0;
}


Thanx in advance
Ashwini

Try Again

if( xyz::control::a == 0)

You don't want 'control' in there.
a,b,c and d are constants in the scope of xyz.
control is a type within the scope of xyz.

So you have xyz::a, xyz::b, xyz::c, xyz::d and xyz::control used:
xyz::control my_value = xyz::a;

Also, in this statement:
typedef enum {a=0,b,c,d} control;

in c++ (as opposed to c) you can just write

enum control {a=0,b,c,d};

Think of it like a struct or class ...
struct control { /* Whatever*/ };

gives you the ability to say:
control c;
in your code.

If you look at c code you will often see something more like
struct control c;
because you do not have the implicit type.

class xyz
{
enum {a=0,b,c,d} control;
}
is giving you a member control of class xyz. of type enum.
preceding this with typedef (as you have and want but do not need to) makes control a type in the scope of xyz.

Yes, it is confusing - it is for me. I would suggest using a reference book just to confirm these points, regarding the precise usage.

It gets pretty in depth.
I might edit this a bit after reading back.
Summary:
I think

Thanx dakensta,

The following code works fine..
#include<iostream>
using namespace std;
class xyz
{
public:
typedef enum {a=0,b,c,d} control;
};
int main()
{
xyz::control d;
d=xyz::a;
cout<<d;
return 0;
}