Storing variable number of data in a class

[Snyke]

Well my problem is simple:
I have a class which has a variable number of members. Lets say I have a
class Family and a variable number of FamilyMembers. Until now I used a
member of Family called members of type List<FamilyMembers> since an
array is unsuitable for the task (unless I'm much mistaken array sizes
can't be modified on runtime, can they?). Now I'm asking myself if there
isn't a better way to handle this problem, since it's a very common problem.

Thanks.

 

[Peter van Merkerk]

Well my problem is simple:
I have a class which has a variable number of members. Lets say I have a
class Family and a variable number of FamilyMembers. Until now I used a
member of Family called members of type List<FamilyMembers> since an
array is unsuitable for the task (unless I'm much mistaken array sizes
can't be modified on runtime, can they?).

The std::vector class is in many cases an excellent alternative for a C
style array, and can be resized during runtime. You can access elements
in a vector just like an array. And operations like adding and removing
elements work just like the std::list class you already know.

Now I'm asking myself if there
isn't a better way to handle this problem, since it's a very common
problem.

What is the problem your having with using the standard container classes?

 

[Mark]

Well my problem is simple:
I have a class which has a variable number of members. Lets say I have a
class Family and a variable number of FamilyMembers. Until now I used a
member of Family called members of type List<FamilyMembers> since an
array is unsuitable for the task (unless I'm much mistaken array sizes
can't be modified on runtime, can they?). Now I'm asking myself if there
isn't a better way to handle this problem, since it's a very common
problem.

Thanks.

Using dynamic arrays you can resize arrays at runtime. But a better
alternative is using the vector class from the standard template
library. For more info, you can look at:
http://www.icce.rug.nl/documents/cplusplus/

--
Mark Moonen
http://perswww.kuleuven.ac.be/Mark_Moonen/

Experience is a dear teacher, and only fools will learn from no other.
Benjamin Franklin

 

[=?ISO-8859-1?Q?=22Nils_O=2E_Sel=E5sdal=22?=]

Well my problem is simple:
I have a class which has a variable number of members. Lets say I have a
class Family and a variable number of FamilyMembers. Until now I used a
member of Family called members of type List<FamilyMembers> since an
array is unsuitable for the task (unless I'm much mistaken array sizes
can't be modified on runtime, can they?). Now I'm asking myself if there
isn't a better way to handle this problem, since it's a very common
problem.

std::list,std::vector and friends are just what you want here, so you
seem to be on the right track. You might store pointers to them though,
if a familymemeber should be manipulated outside the Family class. Though
it makes allocation and deallocation a bit trickier.

 

[Snyke]

What is the problem your having with using the standard container classes?

It's not the fact that it's a standard container class that disturbs me,
but the messy iterator work when using lists

 

[Snyke]

std::list,std::vector and friends are just what you want here, so you
seem to be on the right track. You might store pointers to them though,
if a familymemeber should be manipulated outside the Family class. Though
it makes allocation and deallocation a bit trickier.

For encapsulation matters I use instances and not pointers to them,
since the Design should be good enough to encapsulate the whole thing
or, if not, provide access functions to the member variable

 

[Jeff Flinn]

It's not the fact that it's a standard container class that disturbs me,
but the messy iterator work when using lists

Messy?

std::vector uses iterators as well.

Jeff

 

[Peter van Merkerk]

It's not the fact that it's a standard container class that disturbs me,
but the messy iterator work when using lists

I see, fortunately the elements in a vector can be accessed just like the
elements in an array
Iterators may require some getting used to, but being able to iterate over
elements the same way regardless of the container is a very elegant and
powerful concept. But I understand what you mean with the "messy" part.