From:	joel_hansell AT my-deja DOT com
Newsgroups:	comp.os.msdos.djgpp
Subject:	Array of home-made class, C++ game
Date:	Sun, 28 May 2000 15:54:49 GMT
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To:	djgpp AT delorie DOT com
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In C++ class, I'm supposed to write a simple
slalom game. I'm trying to do this in an
expandable fasion, so I can add new levels,
players and such easily. I use a struct "Port"
for each gate the skier has to pass, and the
object "Game" stores the levels as an array of
such Ports. However, I don't think I'm doing this
quite right, since I keep getting a GFP when I
run it. It compiles ok under djgpp 2.03 (dos),
but at runtime I get the following:

Program exit code 255 (0x00ff)
Call frame traceback:
0x00001019 ???

stderr:
Exiting due to signal SIGSEGV
GPF at eip=00001019, error=2800
and then lots of assembly code. If it would be
helpful, I can post the whole of it.

I believe the problem lies in the "array of
Port". My teacher has so far been unable to
explain to us the use of pointers, so I guess
there should be some *'s and stuff in there...
I've isolated the troublesome code down to this:

#include <stdlib.h>
#include <time.h>

struct Port {
public:
    int x, y, width;
};

class Game {
private:
    int gameOver;
    Port level[]; /* array of Ports, should this
be "Port* level[]" or even "Port[] level"?
Perhaps I must define the size of the array, like
"Port* level[5]"? /*
public:
    Game();
    void setup();
};

Game::Game() {
    gameOver=0;
    for (int i=0; i<5; i++) {
        level[i].x=0;
        level[i].y=0;
        level[i].width=0;
    }
}

void Game::setup() {
    srand(time(NULL));
    for (int i=0; i<5; i++) {        /*Randomizes
the locations of the Ports, and places them 20
pixels below the last one*/
      level[i].x=150+(random() % 200);
      level[i].y=20+i*20;
      level[i].width=30;
    }
}

int main()
{
  Game newgame;
  newgame.setup();
  return 0;
}

Could someone please tell me what would be the
proper way of declaring
the Port array?


--
--
Joel Hansell
http://home.bip.net/jolter



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