Multi-dimension STL vector

Help!
I am trying to use the STL vector multi-dimenstional (I know how to do 2-d but I want to use 3-d

This is what I have tried

vector < vector <vector <int> >> m(3, vector< vector<int> >(4,5));

I also tried the following:

vector < vector <vector <int> >> m(3, vector<int> (5, vector<int> (4)));

I get the similar error as shown above.

Can you please shed some light?

Also is there another way to avoid using 3-d vector if I want to use it for the following

int i,j,k;
float a[i][j][k]=value;

off course I would like to vary the size of array dynamically.

Your help is appreciated.

AD



****************************************************

c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\vector(357): error C2664: 'std::vector<_Ty>::_Construct_n' : cannot convert parameter 2 from 'int' to 'const std::vector<_Ty> &'
with
[
_Ty=std::vector<int>
]
and
[
_Ty=int
]

Use typedefs:

Code:

---

#include <vector>
// To much work!!
std::vector < std::vector <std::vector <int> > >
m(3,std::vector< std::vector<int> >(4, std::vector<int>(4,0)));

// Easier to maintain
typedef std::vector<int> Int1D;
typedef std::vector<Int1D> Int2D;
typedef std::vector<Int2D> Int3D;

int main()
{
  Int3D My3DArray(10, Int2D(10, Int1D(10,0)));
}

---

The reason for the typedefs is that you will at some point may need an iterator. When you define the iterator, what's more easier?

Code:

---

std::vector< std::vector< std::vector<int> > >::iterator it;

---

OR

Code:

---

Int3D::iterator it;

---

Regards,

Paul McKenzie

How do I populate a 3-d stl vector using a for statement?

thank you

Quote:

---

Originally posted by AfricanDude
How do I populate a 3-d stl vector using a for statement?

thank you

---

I don't know exactly what you mean. You mean this?

Code:

---

Int3D My3DArray(10, Int2D(10, Int1D(10,0)));

int size1 =  My3DArray.size();
for ( int i = 0; i < size1; ++i )
{
    int size2 = My3DArray[i].size();
    for (int j = 0; j < size2; ++j )
    {
        int size3 = My3DArray[i][j].size();
        for ( k = 0; k < size3; ++k )
            MyArray[i][j][k] = 15;
    }
}

---

If you are talking about how do you size each of the dimensions, then that is a different question.

Regards,

Paul McKenzie

That is what I did, I wanted to make sure.

Thank you very much for the help.

Good Day!
AD

Quote:

---

Originally posted by AfricanDude
vector < vector <vector <int> >> m(3, vector< vector<int> >(4,5));

vector < vector <vector <int> >> m(3, vector<int> (5, vector<int> (4)));

---

>> is interpreted by the compiler as the right shift operator.

Hello:
I have this interesting problem...
I have to use a c-library that contains a function that is defined as follow:

int func(char * cpData);

I have been using a structure accually a nested structure as follows

struct A
{
char cString;
char cAnotherstring;
}sA;

struct B
{
int iIndex;
float fData[MAXDATA];

}sB;

struct C
{
struct A nA;
struct B nB[8];

}sStream;


I can call this structure with now problems
using
func((char *) &sStream);

The problem happenes when

I wanted to use a vector for the float fData

such as the struct B is as follows:

struct B
{
int iIndex;
vector< float> fData;
} sB;


when I call the function I getting garbaged data.
I do take care of the reserving the appropriate data size for the vector
In fact I can see the data correctly at a point before I used this legecy
function.


Is there a way I can convert somehow to c-array which the function understand
but be able to use the advantage of the vector.

Your speedy reply wiill be vey much appreciated.

AD

So basically you need to serialize the data stored in the vector? That won't happen though a cast to char*. All that gives you is the memory-layout of the vector class itself, not the data it is storing. The same thing would happen if you had c-style strings (char*) in your structs. You would see the pointer, but not the string it is pointing to.

One solution to this is to implement operator >> and << for your structs to enable serialization to a std::ostream. (Or maybe your own serializer class.) Casting pointers like you do now, is something you really, really should not do if you aren't fully aware of the consequences.

Quick question regarding the 3d vector, which way does it display given how you guys created it?

Code:

---

#include <vector>
// To much work!!
std::vector < std::vector <std::vector <int> > >
m(3,std::vector< std::vector<int> >(4, std::vector<int>(4,0)));

// Easier to maintain
typedef std::vector<int> Int1D;
typedef std::vector<Int1D> Int2D;
typedef std::vector<Int2D> Int3D;

int main()
{
  Int3D My3DArray(10, Int2D(10, Int1D(10,0)));
}

---

so lets say:

1d = [3 4 3]
2d = [5 6 5]
3d = [7 8 7]

Would it display as above? just in a matrix?
or does it do down.. like:

[3 5 7]
[4 6 8]
[4 5 7]

Trying to grasp what its doing in code, took a bunch of linear algebra courses but havent applied to code yet.

Just decide on an interpretation of the dimensions and stick with it. You can write your own display function however you want.

I also suggest looking into boost::multi_array.

Displaying a 3-dimensional vector on a 2-dimensional monitor is intrinsically difficult, so I would suggest using a 3D graphic library like OpenGL to display it.

But that's just me...

Quote:

---

Originally Posted by treuss

Displaying a 3-dimensional vector on a 2-dimensional monitor is intrinsically difficult, so I would suggest using a 3D graphic library like OpenGL to display it.

But that's just me...

---

Yeah, thats what we are trying to do actually, were using glut and C++
i think how were gonna manage xyz is a single vector for x, single for y and single for z, just to keep it uncomplicated, then the vertex number would just be associated with the position [i] for any info.

Thanks for the help!

Quote:

---

>> is interpreted by the compiler as the right shift operator.

---

Not necessarily. As with VC 2005, it works! Compiler is smart enough to understand the difference. Yeah, to be on safer side, we should use space in between...