Thread: How do I retrace my steps after a wrong move?

...it's the same program i've been trying to finish for weeks now. I still can't get it to work properly.
Can some loving person please help. I know this is qiute a bit of code to spiel....but this is just to help the kind one to undersand my algorithm.

Please.....
In the main I read the maze and print it( no problem with that). Then using the advance_maze function. Like so....

Code:

.
int main()
{
	Move curr_move;
	Curr_pos pos;
	char Maze[40][40];
	char filename[12];
	int rows = 0;
	int columns = 0;
	MOVEDEQUE A;
		
	
	cout<< "Please enter the name of the maze file you want to read, or (q) to quit.\n" << endl;
	cout<< "(a) maze1.txt\n(b) maze2.txt\n(c) maze3.txt\n"<< endl;
	cin.getline (filename, 10);
	if (filename[0] == 'q')
	{
		return 0;
	}
	Read_file (Maze, &columns, &rows, pos, filename);
	curr_move.maze_col = pos.col;
	curr_move.maze_row = pos.row;
	curr_move.move_number = 3;
	Print_m_array (Maze, rows, columns);
	A.push_back(curr_move);
	
	advance_maze(curr_move, A, Maze, &rows, &columns);
	Print_m_array (Maze, rows, columns);
	
	
	return 0;	
}

.

This is the part that is not working well.

Code:

.

void advance_maze( Move &move, MOVEDEQUE &M, char m_array[][40], int *columns, int *rows)
{
	
	int n;
	n = move.move_number;
	int nxtrow = 0;
	int nxtcol = 0;
	bool blocked;
	bool foundnxt_step;
	//Move current_m;
	
	//M.push_back(move);
	blocked = false;
	foundnxt_step = false;
	while (!M.empty())
	{
		//	move = M.back();
		//  M.pop_back();
		//M.push_back(move);
		
		if (m_array[move.maze_row][move.maze_col] == '0' || m_array[move.maze_row][move.maze_col] == 'E' )
		{
			m_array[move.maze_row][move.maze_col] = '*';
			
			nxtrow = move.maze_row + position[n].vertical;
			nxtcol = move.maze_col + position[n].horizontal;
			move.maze_row = nxtrow;
			move.maze_col = nxtcol;
			
			for (; n<4;n++)
			{
				
				if ( nxtrow < *rows && nxtcol < *columns && m_array[move.maze_row][move.maze_col] == '0')
				{
					
					M.push_back(move);
					//	m_array[move.maze_row][move.maze_col] = '*';
					//move.maze_row = nxtrow;
					//move.maze_col = nxtcol;
					foundnxt_step = true;
					for (; n<4 && foundnxt_step == true; )
					{
						m_array[move.maze_row][move.maze_col] = '*';
						nxtrow = move.maze_row + position[n].vertical;
						nxtcol = move.maze_col + position[n].horizontal;
						move.maze_row = nxtrow;
						move.maze_col = nxtcol;
						
						if(m_array[move.maze_row][move.maze_col] != '0')
						{
							foundnxt_step = false;
							move = M.back();
							//m_array[move.maze_row][move.maze_col] = '0';
							n = 0;
						}
						else
						{
							M.push_back(move);
							//m_array[move.maze_row][move.maze_col] = '*';
						}
					}
					
					
					
					/*if (m_array[nxtrow][nxtcol] != '0')
					{
					foundnxt_step = false;
					n=0;
				}*/
					
				}
				else if (m_array[move.maze_row][move.maze_col] == 'X')
				{
					M.pop_back();
					cout<< " Yah!!! Maze solved!! "<< endl;
					break;
				}
				if (foundnxt_step == false)
				{
					//M.pop_back
					for (; n<4 && foundnxt_step == false; n++ )
					{
						//n++;
						nxtrow = move.maze_row + position[n].vertical;
						nxtcol = move.maze_col + position[n].horizontal;
						move.maze_row = nxtrow;  
						move.maze_col = nxtcol;   
						
						
						if (m_array[move.maze_row][move.maze_col] == '0')/// Why does it complain about a stack
						{                                                    /// overflow here?
							foundnxt_step = true;
							///M.push_back(move);
							//n =0;
						}
					}
					if (n>3 && m_array[nxtrow][nxtcol] != '0')
					{
						blocked = true;
						M.pop_back();
						move =  M.back();
					}
					
				}
				
			}
		}
		
	}
	
	if (M.empty() && blocked == true)
	{
		cout<< "Awwww... sorry, this maze cannot be solved."<< endl;
	}
}

.

Thanks for taking a peek.!Really i'm very grateful.

I would like to help, but unfortunately the code is rather hard to follow without more information. Is there anyway you can go back and comment everything then repost the code? Otherwise it'll take forever trying to guess what logic and methods you are using which will make it impossible to fix your error.