Is it possible to create a vector of vector?

[Ramon F Herrera]

Newbie alert: I come from the C side, struggling to learn C++.

I need a two-dimensional data structure. I first tried a regular
vector and added the 2nd dimension with my own structs and pointers. I
couldn't make it work. Too many illegal assignments.

My next attempt was to create a vector of vector (or list of vector,
etc.). The compiler (MSVC++) doesn't seem to like such structure. I
guess I could try gcc, but let's hear the experts' opinions.

Your suggestions are most welcome.

-RFH

[LR]

Ramon F Herrera wrote:

My next attempt was to create a vector of vector (or list of vector,
etc.).

This seems a very reasonable approach.

The compiler (MSVC++) doesn't seem to like such structure.

Can you please post a small example that demonstrates the problem.

Can you also be more specific about the problem that you're having.
LR

[Mauro Ciancio]

On 2 jun, 23:38, Ramon F Herrera <ra...@conexus. netwrote:

Newbie alert: I come from the C side, struggling to learn C++.

I need a two-dimensional data structure. I first tried a regular
vector and added the 2nd dimension with my own structs and pointers. I
couldn't make it work. Too many illegal assignments.

My next attempt was to create a vector of vector (or list of vector,
etc.). The compiler (MSVC++) doesn't seem to like such structure. I
guess I could try gcc, but let's hear the experts' opinions.

Your suggestions are most welcome.

-RFH

Mi english is not so good. Im trying to explain.

For example:

std::vector< std::vector<int myVector; // this creates a vector of
vector of integers

Now, you can do this:

std::vector<int vector;
vector.push_bac k(1);

myVector.push_b ack(vector);

then:

std::cout << myVector[0][0] << std::endl; // this prints 1

If you want to initialize a vector of vector with a fixed size use the
following line:

std::vector< std::vector<int myVector (number_of_rows ,
std::vector<int >(number_of_col ums, default_value)) ;

Read http://www.sgi.com/tech/stl/Vector.html to understand the
constructor calls.

I hope you understand.

Regards
--
Mauro Ciancio

[Daniel Pitts]

Ramon F Herrera wrote:

Newbie alert: I come from the C side, struggling to learn C++.

I need a two-dimensional data structure. I first tried a regular
vector and added the 2nd dimension with my own structs and pointers. I
couldn't make it work. Too many illegal assignments.

My next attempt was to create a vector of vector (or list of vector,
etc.). The compiler (MSVC++) doesn't seem to like such structure. I
guess I could try gcc, but let's hear the experts' opinions.

Your suggestions are most welcome.

-RFH

#include <vector>

int main(int argc, char *argv[]) {
std::vector<std ::vector<int vectovect;
vectovect.resiz e(20);
for (std::vector<st d::vector<int:: iterator i = vectovect.begin ();
i != vectovect.end() ; ++i) {
i->resize(30);
}
}

--
Daniel Pitts' Tech Blog: <http://virtualinfinity .net/wordpress/>

[Daniel Pitts]

Daniel Pitts wrote:

Ramon F Herrera wrote:

>Newbie alert: I come from the C side, struggling to learn C++.

I need a two-dimensional data structure. I first tried a regular
vector and added the 2nd dimension with my own structs and pointers. I
couldn't make it work. Too many illegal assignments.

My next attempt was to create a vector of vector (or list of vector,
etc.). The compiler (MSVC++) doesn't seem to like such structure. I
guess I could try gcc, but let's hear the experts' opinions.

Your suggestions are most welcome.

-RFH

#include <vector>

int main(int argc, char *argv[]) {
std::vector<std ::vector<int vectovect;
vectovect.resiz e(20);
for (std::vector<st d::vector<int:: iterator i = vectovect.begin ();
i != vectovect.end() ; ++i) {
i->resize(30);
}
}

Ah, listen to Mauro's advice. I didn't know about those constructors
that would ease your use :-)

--
Daniel Pitts' Tech Blog: <http://virtualinfinity .net/wordpress/>

[Ramon F Herrera]

On Jun 2, 11:50 pm, LR <lr...@superlin k.netwrote:

Ramon F Herrera wrote:

My next attempt was to create a vector of vector (or list of vector,
etc.).

This seems a very reasonable approach.

The compiler (MSVC++) doesn't seem to like such structure.

Can you please post a small example that demonstrates the problem.

Well, I figured out that it is possible to create such contraptions.
There are at least two ways:

typedef vector<RadioBut tonNode> RadioButtonGrou p;
vector<RadioBut tonGroup> ListOfRadioButt on;

and the more succinct:

vector<vector<R adioButtonNode> ListOfRadioButt on;

Now I have to investigate the kind suggestions from Mauro and Daniel.

Thanks, Daniel!
Grazie tanti, Mauro!

-Ramon

[red floyd]

Ramon F Herrera wrote:

On Jun 2, 11:50 pm, LR <lr...@superlin k.netwrote:

>Ramon F Herrera wrote:

>>My next attempt was to create a vector of vector (or list of vector,
etc.).

This seems a very reasonable approach.

>>The compiler (MSVC++) doesn't seem to like such structure.

Can you please post a small example that demonstrates the problem.

Well, I figured out that it is possible to create such contraptions.
There are at least two ways:

typedef vector<RadioBut tonNode> RadioButtonGrou p;
vector<RadioBut tonGroup> ListOfRadioButt on;

and the more succinct:

vector<vector<R adioButtonNode> ListOfRadioButt on;

Your problem is here. The compiler is interpreting the closing >as a
single token. Put a space between them:

vector<vector<R adioButtonNode ListOfRadioButt on;

Note the space.

>
Now I have to investigate the kind suggestions from Mauro and Daniel.

Thanks, Daniel!
Grazie tanti, Mauro!

-Ramon

[Tim Love]

William Xu <wi*********@gm ail.comwrites:

>red floyd <no**********@e xample.comwrite s:

>Note the space.

>Which is really annoying...

Don't worry - I think it's fixed in the next release.

[Daniel T.]

Ramon F Herrera <ra***@conexus. netwrote:

Newbie alert: I come from the C side, struggling to learn C++.

I need a two-dimensional data structure. I first tried a regular
vector and added the 2nd dimension with my own structs and pointers. I
couldn't make it work. Too many illegal assignments.

My next attempt was to create a vector of vector (or list of vector,
etc.). The compiler (MSVC++) doesn't seem to like such structure. I
guess I could try gcc, but let's hear the experts' opinions.

Your suggestions are most welcome.

Don't make a vector of vectors. Better would be to make a matrix class
that is inherently 2D. See the FAQ for an example.

[Kai-Uwe Bux]

Daniel T. wrote:

Ramon F Herrera <ra***@conexus. netwrote:

>Newbie alert: I come from the C side, struggling to learn C++.

I need a two-dimensional data structure. I first tried a regular
vector and added the 2nd dimension with my own structs and pointers. I
couldn't make it work. Too many illegal assignments.

My next attempt was to create a vector of vector (or list of vector,
etc.). The compiler (MSVC++) doesn't seem to like such structure. I
guess I could try gcc, but let's hear the experts' opinions.

Your suggestions are most welcome.

Don't make a vector of vectors. Better would be to make a matrix class
that is inherently 2D. See the FAQ for an example.

That depends very much on whether the 2D structure is rectangular or whether
it is ragged like a text broken up into lines of different length.

For a rectangular array, a matrix like container class is probably the way
to go as it guarantees the invariants for rectangularity. For a ragged
structure, I don't see what is wrong with a vector of vectors. Of course,
one can always encapsulate that in a class to hide implementation details.
But whether that is worth the effort cannot be said without knowing the
particulars of the project. (And, for all we know, the OP might be asking
about how to implement the internals of a text buffer class.)
Best

Kai-Uwe Bux