Dynamically SIzed Global Matrix problems

This is a discussion on Dynamically SIzed Global Matrix problems within the C++ Programming forums, part of the General Programming Boards category; I'm working on a game that uses a class which creates a matrix for a bunch of tiles. What i ...

  1. #1
    Registered User Josh Kasten's Avatar
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    Jul 2002
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    Dynamically SIzed Global Matrix problems

    I'm working on a game that uses a class which creates a matrix for a bunch of tiles. What i want to do, is to be able to pass to the class, when it is created, the xtiles, and ytiles, for example:

    int *matrix;

    void setup(int xtile, int ytile)
    {
    matrix=new int[ytile] [xtile];
    }

    void main()
    {
    setup(30,40);
    }

    and that would resize the array to be 30 across, and 40 down, but when i compile in Visual C++, it says something about how it can't convert from one int to another.......if you know how to fix this, I would be greatful for a reply, thank you!
    int a; don't make a program without it.

  2. #2
    Programming Sex-God Polymorphic OOP's Avatar
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    You can't directly dynamically allocate a multidimensional array.

    What you want to do is allocate an array of size numrows times numcols and access indices in it by RowToAcces * NumCols + ColToAccess.

    Or you can allocate an array of size numcols which would be pointers to the datatype you are making an array of and then dynamically allocate each column individually, but this method is not a good idea.

    Also, don't use void main use int main. kthxbai.

  3. #3
    Registered User rmullen3's Avatar
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    330

    ~

    Code:
    int *matrix;
    int Width, Height;
    
    void setup (int xtile, int ytile)
    {
          matrix = new int[ytile*xtile];
          Width = xtile;
          Height = ytile;
    }
    
    __inline int GetTile (int x, int y) 
    {
        return matrix[(y * Width) + x];
    }
    "He who makes a beast of himself, gets rid of the pain of being a man." Dr. Johnson

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