Thread: segment fault?

I dont' know what this is... it gives me a run-time error (the program just craps)... I debugged it and the debugger said it was an "access violation (segment fault)" here:

Code:

	for(v=0;v<vertical;v++)	//loop through rows
	{
		if(debug)
   			vcount++;
		for(h=0;h<horizontal;h++) 	//loop through cols
		{
			if(debug)
				hcount++;
			tank[v][h]=emptychar;	//fill with empty space
		}
	}

and that is part of this class:

Code:

class lifeClass
{
	public:
		lifeClass(unsigned int,unsigned int,unsigned int);
  			//constructor (tank length,tank width,organism#)
		void step();	//step through program
		bool debg();	//returns bool debug
		bool nextstep();	//returns true for another generation
		~lifeClass();	//destructor
	private:
  		void randxy(unsigned int&,unsigned int&);	//randomizes X and Y
  		void drawtemptank();	//debug - Draws temporary tank
		void drawtank();	//draws tank to screen
		void copytank();	//copies next tank to current tank
		char live(unsigned int,unsigned int);	//living characters
		char die(unsigned int,unsigned int);	//dying characters
		unsigned int countNeighbors(unsigned int,unsigned int);	//counts neighbors
		
		bool debug;	//debugging statements - see lifeClass
		
		bool cont;	//continue to next generation?
		char tank[][];	//living space
		char emptychar,fillchar,killchar,bornchar;	//characters used
 		unsigned int vertical,horizontal;	//length and width of living space
		unsigned int clickcount;	//counts clicks (steps) taken by the program
};

I would appreciate some help with what this is, and if there's a better way (which I'm sure there is) to write a 2D (array of arrays) array, please post...

secondly, you define a new char array like this

Code:

char *array=new char[int];

but how/can you do that for a 2D array? and how do you delete a 2D array?

sorry for all the questions, but, well, I have a lot of questions

but how/can you do that for a 2D array? and how do you delete a 2D array?

I think you just have to allocate it one element at a time or one dimension at a time (?)

Code:

  for(int x=0;x<ROWS;x++)
     for(int y=0;y<COLS;y++)
           array[x][y]=new Type;

But I could be incorrect...

EDIT:

This seems to work:

Code:

int *array[10];
  for(int x=0;x<10;x++)
           array[x]=new int[10];
//or
int *array[10][10]
     for(int x=0;x<10;x++)
        for(int y=0;y<10;y++)
               array[x][y]=new int[10];

JaWiB's example is essentially a 3D array (though in essence, correct). To do this, I recommend using stl::vector, or a matrix class of some sort (or other vector class). Anyways, if this is the way you want to do it, here is a small example:

Code:

int** array2d = new int*[10];
for(int i = 0; i < 10; ++i)
  array2d[i] = new int[10];

... etc ...

for(int j = 0; j < 10; ++j)
  delete array2d[j];
delete array2d;

Cheers

cool thanks for all the help... I would do vectors, but I don't know how to use them/exactly what they are... =/ I still need to look into that some time...