?
Solved

2D Dynamic Arrays

Posted on 2004-10-03
11
Medium Priority
?
242 Views
Last Modified: 2010-04-01
Hi,

How do I make a two-dimensional dynamic array? And is it possible to make one from a class?
0
Comment
Question by:SonicX_BlueBlur
  • 4
  • 3
  • 2
  • +1
11 Comments
 
LVL 55

Expert Comment

by:Jaime Olivares
ID: 12214035
Hi SonicX_BlueBlur,

You can design your own class to manage a bidimensional dynamic class.
Have a look to this similar question I've answered for a 3-dimensional dynamic class:
http://www.experts-exchange.com/Programming/Programming_Languages/MFC/Q_21021623.html

Good luck,
Jaime.
0
 
LVL 17

Expert Comment

by:rstaveley
ID: 12214211
EE's Axter has this implementation, which he posted a while back, which is nice:

http://axter.com/code/dynamic_2d_array.h
0
 

Author Comment

by:SonicX_BlueBlur
ID: 12214375
rstaveley, Axter's code is illegible to me. So far, Jaime's code looks the best, but I don't know how I could make it work with a class.
0
What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

 
LVL 55

Expert Comment

by:Jaime Olivares
ID: 12214419
Here is a 2d implementation with a 'double' data member, hope you can understand. I will continue tomorrow because I am going to sleep. Good luck, Jaime.

---------------------------------

class Double2dArray
{
      double *data;   // example with 'double' datatype, could be anything
      int maxx, maxy;

      Double3dArray (int x, int y) {
             maxx = x;
             maxy = y;
             data = new double[maxx*maxy];
      }
      ~Double3dArray () {
           delete [] data;
      }
      inline double GetAt(int x, int y) {
           return data[x*maxy*y];
      }
      inline SetAt(int x, int y, int z) {
           data[x*maxy*y] = val;
      }
};

How to use:

Double2dArray arr(200,200);
arr.SetAt(100,30);    // Set element 100,30
double value = arr.GetAt(100,30);  // Get value of element 100,30

0
 

Author Comment

by:SonicX_BlueBlur
ID: 12214494
Yes, I know. I read that same code on that other thread, but how would I call member functions using that 2D array code to make a class array?
0
 
LVL 30

Accepted Solution

by:
Axter earned 580 total points
ID: 12214683
http://axter.com/code/dynamic_2d_array.h

If you use my code, you can easily create a 2 Dimensional array using the following method:

dynamic_2d_array<int> MyArrOfInt(33, 44);

Where 33 is one dimension, and 44 is the second.

The above example created and interger array.

Following is a char array:

dynamic_2d_array<char> myarray(row, col);
0
 
LVL 30

Expert Comment

by:Axter
ID: 12214695
To access the data in the array, you just use the same syntax as if you were using a C-Style array.

MyArrOfInt[22][11] = 1234;

cout << MyArrOfInt[22][11] << endl;

The dynamic_2d_array class is very generic, simplistic, and efficient.

Since it uses the same interface as a C-Style array, it makes it easier to use and maintain.
0
 
LVL 30

Expert Comment

by:Axter
ID: 12214711
>>but I don't know how I could make it work with a class.

To use Jaime's code, you would have to change his original, since it's not a template class.

If you use the dynamic_2d_array, you don't have to change the class.
You just declare it with your class name in the template ID.

dynamic_2d_array<MyClass> my_var(x, y);
0
 

Author Comment

by:SonicX_BlueBlur
ID: 12216257
...Geez, it's that easy? And I thought this was all way above my head :P
Thanks for clearing that up, Axter. 145 points to you.
0
 
LVL 17

Expert Comment

by:rstaveley
ID: 12218882
I'm glad you accepted that from Axter rather than me. It would have been embarrassing 8-)
0
 
LVL 30

Expert Comment

by:Axter
ID: 12219336
>>I'm glad you accepted that from Axter rather than me. It would have been embarrassing 8-)

IMHO, I think the points should have been split.

I steal jkr's answers all the time. :-)
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Errors will happen. It is a fact of life for the programmer. How and when errors are detected have a great impact on quality and cost of a product. It is better to detect errors at compile time, when possible and practical. Errors that make their wa…
Introduction This article is the first in a series of articles about the C/C++ Visual Studio Express debugger.  It provides a quick start guide in using the debugger. Part 2 focuses on additional topics in breakpoints.  Lastly, Part 3 focuses on th…
The viewer will learn how to pass data into a function in C++. This is one step further in using functions. Instead of only printing text onto the console, the function will be able to perform calculations with argumentents given by the user.
The viewer will learn how to clear a vector as well as how to detect empty vectors in C++.
Suggested Courses

850 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question