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linearize n-dimesionality

sajis997 (109)
Hello forum,

I have the following code snippet that represent the 2D array in the linear manner .

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  int i, j;

  for (i = 0; i < dy; i++) //height 
    {
      for (j = 0; j < dx; j++) //width
	{
	  p[i*dx+j] = (j+0.5f+(myrand() - 0.5f))/dx;
	}
    }


I am getting hard time to make it functional if add one more dimension in the following way:

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  int i, j, k;

  for (i = 0; i < dy; i++) //height 
    {
      for (j = 0; j < dx; j++) //width
	{
          for(k = 0; k < dz; k++)
          {  
	      p[HELP NEEDED HERE] = (j+0.5f+(myrand() - 0.5f))/dx;
          }
	}
    }



Any help is greatly appreciated.


Regards
Sajjad

Chervil (7320)
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#include <iostream>
#include <iomanip>

    using namespace std;

int main()
{
    const int dx = 2;
    const int dy = 3;
    const int dz = 5;

    const int totalsize = dx * dy * dz;

    int p[totalsize];

    for (int i=0; i< totalsize; i++)
    {
        p[i] = i + 1;
    }


    for (int y = 0; y < dy; y++) // height
    {
        for (int x = 0; x < dx; x++) // width
        {
            for (int z = 0; z < dz; z++) // depth
            {
                int ix  = z  + x*dz  + y*dz*dx;

                cout << setw(5) << p[ix];
            }
            cout << endl;
        }
        cout << "---------------------------\n";
    }

    cout << "\n\n ...........................\n\n\n";



    for (int z = 0; z < dz; z++) // depth
    {
        for (int y = 0; y < dy; y++) // height
        {
            for (int x = 0; x < dx; x++) // width
            {
                int ix  = x  + y*dx  + z*dx*dy;

                //int ix  = z  + x*dz  + y*dz*dx;

                cout << setw(5) << p[ix];
            }
            cout << endl;
        }
        cout << "------------\n";
    }

    return 0;
}

    1    2    3    4    5
    6    7    8    9   10
---------------------------
   11   12   13   14   15
   16   17   18   19   20
---------------------------
   21   22   23   24   25
   26   27   28   29   30
---------------------------


 ...........................


    1    2
    3    4
    5    6
------------
    7    8
    9   10
   11   12
------------
   13   14
   15   16
   17   18
------------
   19   20
   21   22
   23   24
------------
   25   26
   27   28
   29   30
------------


Be careful about the relative order of x,y and z.
Try replacing line 47 with line 49 and see what happens.

If I was doing this, I'd encapsulate it inside a class, to make sure that the index was always correctly calculated.
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