From: dmt AT bigfoot DOT com (Jeff W./DMT)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: PLEASE help with vectors!
Date: Wed, 22 Apr 1998 22:29:38 GMT
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To: djgpp AT delorie DOT com
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well, I got a great suggestion which is to implement a vector class as
follows (assuming your data is of integer type):


typedef struct BaseType
{
 //base layer of tiles
 int tileno; //which tile number to load from the datafile
 int opaque; //can you see past the tile? For line of sight algorithm
 int collision; //for collision detection, see #defines
 int flag; //misc flag
};

class vector
{
public:
  vector (void)
  {
    width = 20; //arbitrary starting map size of 20x15
    height = 15;
    data = new int[width * height];
  }
  ~vector (void)
  {
    delete[] data;
  }

  int resize (const int _width, const int _height)
  {
    if ((_width <= 0) || (_height <= 0))
      return -1;
    width = _width;
    height = _height;
    delete[] data;
    data = new int[width * height];
    return 0;
  }

  int* operator[] (const int _y)
  {
    /* FIXME: test for index out of range.  */
    return &data[_y * width];
  }

private:
  int width;
  int height;
  int* data;
};


however, my data type is not an INT, it's a struct containing 4
structs as follows:

typedef struct FringeType
//non-pickupable objects
{
 int tileno;
 int flag;
};

typedef struct ObjType
//normal objects
{
 int tileno;
 int active; //shouldit be blitted???
 int flag;
};

typedef struct RoofType
//for the roof of buildings/etc
{
 int tileno;
 int flag;
};

typedef struct MapStruct
//just contains all the other structures into 1
{
 BaseType base;
 FringeType fringe;
 ObjType obj;
 RoofType roof;
};


NOTE: MapStruct is the main structure, i.e. instead of having DATA as
type int, it should be type MapStruct.  Sooooo, the problem becomes
this: When you use the [] operator, how can I make it so that I know
what field to access??  I.e. what I would ideally like to be able to
do is to say:
AMap[40][2].base.tileno = 5;  or something similar.  

 --Jeff W.

 "The finding of DMT in normal human body fluids
 opens up interesting moral and legal questions.
 Since DMT is illegal, as is 'any substance, compound
 or mixture' containing DMT, it would seem that we
 are all guilty of possesion of a controlled substance"
 -Jonathon Ott

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