Re: Static struct array or array of array

MrAsm <>
Fri, 13 Apr 2007 08:51:58 GMT
On Fri, 13 Apr 2007 09:32:27 +0200, mosfet <>

enum EFileType
ePhoto = 0,

{ "jpg", "jpeg", "gif", "bmp", "png", "", "", "", "", "", "", "", ""},
{ "mp3", "aiff", "mid", "wav", "", "", "", "", "", "", "", "", ""},

BOOL IsAValidFile(char* a_FileExtension, EFileType a_Filetype)

How can I build something like that with a static data structure.
Should I declare an array of const char* ?

(Even if it is not very MFC related.... :)

I think that your approach of using raw C array and raw C (char *)
strings is very old and obsolete (Joe would tell us: "Something like
the punch-cards!" :)

We are in the C++ (and even managed code! :) era.
So, if you are not developing an operating system kernel or device
driver, you should consider C++ with OO and not raw C.

I believe you should do a more object-oriented C++ approach, that will
give you a more robust, readable and extensible code.

Below you can find some code that seems to work.
There is a class called StringList which is a thin wrapper over
std::vector< std::string >.

And there is the FileExtensionChecker class (that uses the StringList)
and exposes the method "IsAValidFile" as you described in your post.
You can use that class as following:

 FileExtensionChecker extChecker;
 extChecker.IsAValidFile( "gif", FileExtensionChecker::ePhoto );
 extChecker.IsAValidFile( "mid", FileExtensionChecker::eMusic );

Note that you have just two kind of file types (photo and music); so I
used simple if's in the implementation. But if you have more file
types, you may consider implementing a more advanced and scalable
solution using std::map to create a map between the kind of file
(photo, music, ...) and the StringList of valid extensions:

  map: KindOfFile --> ExtensionsStringList


#include <iostream>
#include <string>
#include <vector>
#include <algorithm> // find

// Containers for some strings
class StringList


    // Add a new string to the container
    StringList & StringList::Add( const std::string & s );

    // Remove all strings
    void StringList::Clear();

    // Number of strings
    size_t StringList::Count() const;

    // Is the input string stored into the container?
    bool StringList::Contains( const std::string & s ) const;


    // Implement using std::vector
    typedef std::vector< std::string > StringListT;
    StringListT m_strings;


inline StringList & StringList::Add( const std::string & s )
    m_strings.push_back( s );
    return *this;

inline void StringList::Clear()

inline size_t StringList::Count() const
    return m_strings.size();

    // Nothing to do

bool StringList::Contains( const std::string & s ) const
    if ( m_strings.empty() )
        return false;

    if ( std::find(
        ) == m_strings.end() )
        return false;

    return true;


class FileExtensionChecker

    enum EFileType
        ePhoto = 0,


    bool IsAValidFile( const std::string & fileExtension,
                       EFileType fileType ) const;

    StringList m_photoExtensions;
    StringList m_musicExtensions;

    void Init();


void FileExtensionChecker::Init()


bool FileExtensionChecker::IsAValidFile(
        const std::string & fileExtension,
        EFileType fileType ) const
    if ( fileType == ePhoto )
        return m_photoExtensions.Contains( fileExtension );
    else if ( fileType == eMusic )
        return m_musicExtensions.Contains( fileExtension );
        return false;



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