singleton for vector data?

[U7Development]

Hi!.

i have a form where user adds contacts, the form contains fields like name, phone and address.

Each registered contact contains an unique register number, so i think a map is the key to go, where the first type is the contact class

What about creating a singleton containing this map ? so every form can get an instance of this unique map?

[jhx76]

Hi U7Development,

That's not a bad idea to make it a singleton, but this kind of consideration mainly depends on the other needs in your application.
The main question is : will you need, in the future, to store contacts in another separated container for any reason ?

About the map container, IMO, it is the right way.

bye :)

[mrjj]

Hi
Singletons are not really good design for sharing data in most cases as its
more a global variable than anything else.

It's better just to give the map a parameter to the classes that need it.

so in main class or main.cpp
std::map<Qstring, Contact > Contacts;

and then
simply

MyDialog *Dia = new MyDialog (this, Contacts ) ;
and you just change the default constructor to
MyDialog (QWidget *parent , std::map<Qstring, Contact > & Contacts );

and you can use it in that class.