Problem instatiating a template container

[Ulrich Hobelmann]

Hi, how do I correctly instantiate a template container? Everywhere I
look they only mention in-place containers, i.e. construction on the
stack like "List<Bla> myList;".

I tried
List<sometype *> * ls = new List(); which complains (with G++ 4):
expected type specifier before List; cannot convert 'int*' to
'sometype*' in assignment; expected ',' or ';' before 'List'.

(btw: List is my own class, in case you're wondering, but I think a
general answer would be just as fine).

I also tried Java syntax:
List<sometype *> * ls = new List<sometype *>();

but it doesn't work either.

I seriously can't comprehend the error message. Yes, the statement
before the initialization ends with a ';'.

 

[Ulrich Hobelmann]

Hi, how do I correctly instantiate a template container? Everywhere I
look they only mention in-place containers, i.e. construction on the
stack like "List<Bla> myList;".

I tried
List<sometype *> * ls = new List(); which complains (with G++ 4):
expected type specifier before List; cannot convert 'int*' to

Sorry, this line should read "cannot convert 'int*' to

 

[stain]

You don't only have to specify the type for the pointer but also for
the call to "new". Hence
List<sometype *> * ls = new List<sometype*>();
should work. Often you do a typedef before instanciting the list. Like
this:
typedef list<int> intlist;
intlist * myList = new intlist();

Also note that the elements contained in the std::list will be stored
on the heap. Only the container object will be on the stack for calls
like:
list<bla> myList;

 

[Rolf Magnus]

Hi, how do I correctly instantiate a template container? Everywhere I
look they only mention in-place containers, i.e. construction on the
stack like "List<Bla> myList;".

I tried
List<sometype *> * ls = new List(); which complains (with G++ 4):
expected type specifier before List; cannot convert 'int*' to
'sometype*' in assignment; expected ',' or ';' before 'List'.

Why do you want to allocate the container dynamically?

(btw: List is my own class, in case you're wondering, but I think a
general answer would be just as fine).

I also tried Java syntax:
List<sometype *> * ls = new List<sometype *>();

but it doesn't work either.

What does "doesn't work either" mean? This one looks right.

 

[Ulrich Hobelmann]

Why do you want to allocate the container dynamically?

To store it somewhere else

(in another struct in this case)

What does "doesn't work either" mean? This one looks right.

Hm, after reading stain's post, I noticed that, too. Maybe the first
time I accidentally didn't save my file, because the error message still
appeared.

Well, thanks for clearing that up... works great now.