Using enum in class

[dev_15]

Hi, I have this problem that i want to use an enum as a return value
of a private method in my class, but compiler won't let me use as such

Code here:

class CDisplayUtil
{
public:
enum DISPLAYMODE
{
LANDSCAPE = -1,
SQUARE = 0,
PORTRAIT = 1
};

public:
CDisplayUtil();
public:

virtual ~CDisplayUtil(v oid);
private:
DISPLAYMODE GetDisplayMode( );
};



CDisplayUtil::C DisplayUtil()
{
}

CDisplayUtil::~ CDisplayUtil()
{
}

DISPLAYMODE CDisplayUtil::G etDisplayMode()
{
INT nWidth = GetSystemMetric s(SM_CXSCREEN);
INT nHeight = GetSystemMetric s(SM_CYSCREEN);

if(nHeight nWidth)
return PORTRAIT;

if(nHeight < nWidth)
return LANDSCAPE;

return SQUARE;
}

What's wrong?

[=?UTF-8?B?RXJpayBXaWtzdHLDtm0=?=]

Re: Using enum in class

On 2007-10-22 11:24, dev_15 wrote:

Hi, I have this problem that i want to use an enum as a return value
of a private method in my class, but compiler won't let me use as such
>
Code here:
>
class CDisplayUtil
{
public:
enum DISPLAYMODE

All uppercase names are usually reserved for macros. An enumeration is a
type just like a class, so perhaps EDisplayMode would be a more suitable
name.

{
LANDSCAPE = -1,
SQUARE = 0,
PORTRAIT = 1

Again, Landscape, Square, and Portrait might be better names.

};
>
public:

You do not need to put public before every member, only when you want to
change visibility.

CDisplayUtil();
public:
>
virtual ~CDisplayUtil(v oid);
private:
DISPLAYMODE GetDisplayMode( );
};
>
>
>
CDisplayUtil::C DisplayUtil()
{
}
>
CDisplayUtil::~ CDisplayUtil()
{
}
>
DISPLAYMODE CDisplayUtil::G etDisplayMode()

CDisplayUtil::D ISPLAYMODE CDisplayUtil::G etDisplayMode()

The enumeration is part of the class.

{
INT nWidth = GetSystemMetric s(SM_CXSCREEN);

What is wrong with the old honest int?

INT nHeight = GetSystemMetric s(SM_CYSCREEN);
>
if(nHeight nWidth)
return PORTRAIT;
>
if(nHeight < nWidth)
return LANDSCAPE;
>
return SQUARE;
}
>
What's wrong?

--
Erik Wikström

[dev_15]

Re: Using enum in class

Thanks Erik. it just Windows programming they have all
their types and enums in Uppercase

[robin]

Re: Using enum in class

On Oct 22, 5:24 pm, dev_15 <naumansulai... @googlemail.com wrote:

Hi, I have this problem that i want to use an enum as a return value
of a private method in my class, but compiler won't let me use as such
>
Code here:
>
class CDisplayUtil
{
public:
enum DISPLAYMODE
{
LANDSCAPE = -1,
SQUARE = 0,
PORTRAIT = 1
};
>
public:
CDisplayUtil();
public:
>
virtual ~CDisplayUtil(v oid);
private:
DISPLAYMODE GetDisplayMode( );
>
};
>
CDisplayUtil::C DisplayUtil()
{
>
}
>
CDisplayUtil::~ CDisplayUtil()
{
>
}
>
DISPLAYMODE CDisplayUtil::G etDisplayMode()
{
INT nWidth = GetSystemMetric s(SM_CXSCREEN);
INT nHeight = GetSystemMetric s(SM_CYSCREEN);
>
if(nHeight nWidth)
return PORTRAIT;
>
if(nHeight < nWidth)
return LANDSCAPE;
>
return SQUARE;
>
}
>
What's wrong?

Once you define an enum inside a class, this class also defines a
namespace meanwhile. Therefore, here if you want to use DISPLAYMODE
enum, you should specify its namespace, that is, the class name in
which this enum is defined.

The correct lines of code should be:

1). CDisplayUtil::D ISPLAYMODE CDisplayUtil::G etDisplayMode() {...}
2).
if(nHeight nWidth)
return CDisplayUtil::P ORTRAIT;
if(nHeight < nWidth)
return CDisplayUtil::L ANDSCAPE;
return CDisplayUtil::S QUARE;

The function declaration of
private:
DISPLAYMODE GetDisplayMode( );
does not need to go with the class name because this function
declaration is still inside the class CDisplayUtil scope, and the
definition of DISPLAYMODE is visible. But when you define the member
function after the closing brace('}') of class CDisplayUtil, which
means you go out of the scope of CDisplayUtil and into the global
scope now, the DISPLAYMODE becomes invisible, and you need to give the
full qualified name to help compiler find it.

Regards,
-robin