Thread: Help my c++ program

Hello:

I already finished my program, but i cannot print out the result on the screen, and i think there have a few logical problems.

Here is the instruction:

Write a program to read a maze from a text file into your array, print the unsolved maze, solve the maze, and then print the solution. You may assume the maze will fit in a 24-row by 80-column array. The maze will be in a file with the number of rows and columns on the first line, followed by the lines defining the maze, with '*' representing a wall and ' ' (space) representing a corridor. For example, here is a small (8-by-12) maze (on my web site as maze8-12.txt):

8 12
**********
* * *
* ****** *
***** *
* ******
*** *** *
* ** *
**********

You may assume that the maze will always have a solution. The program is easily generalized to show if there is no solution, but this is not required for this assignment. For an n-by-m maze held in a char array a[n][m], the starting point (at the top left) is a[0][0], and the ending point (at the bottom right) is at a[n-1][m-1]. When you print the solved maze, show the path through the maze by marking all points in the solution set with '#'. For example, here is the same maze printed showing the solution:

##**********
*#*########*
*###******#*
*****######*
* ###******
***#***####*
* #####**#*
**********##

Notice, moves down "blind alleys" are left off the solution. I will discuss the algorithm for this in class, and you must use the recursive backtracking algorithm I give you for this program. This is not a large program- about two pages of code.

8 12
**********
* * *
* ****** *
***** *
* ******
*** *** *
* ** *
**********

Here is my code:

Code:

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

char map[24][80];
bool nnew[24][80];
int n, m;

// print maze solution
void print()
{
  cout << endl << "Solution = " << endl;
  int i, j;
  for (i = 0; i < n; ++i, cout << endl)
    for (j = 0; j < m; ++j)
      cout << map[i][j];

  exit(0);
}

void dfs(int i, int j)
{
  // range coordinates check
  if (!(i >= 0 && i < n && j >= 0 && j < m))
    return;
  // do not processing walls and earlier marked cells
  if (map[i][j] == '*' || nnew[i][j])
    return;

  // memorize char of the map
  char ch = map[i][j];
  // put in this cell segment of our future path
  map[i][j] = '#';
  // marked cell, we only moved to the unmarked positions
  nnew[i][j] = 1;

  // yes!
  if (i == n - 1 && j == m - 1)
    print();
  
  // process all 4 directions
  dfs(i - 1, j);
  dfs(i, j + 1);
  dfs(i + 1, j);
  dfs(i, j - 1);

  // restore map
  map[i][j] = ch;
  nnew[i][j] = 0;
}

int main()
{
	ifstream cin("c:\maze8-12.txt");
  
  cin >> n >> m;

  int i, j;
  string str;
  
  // ignore \n symbol
  cin.ignore();
  for (i = 0; i < n; ++i)
  {
    // read string describing new row of the map
    getline(cin, str);
    for (j = 0; j < m; ++j)
      // construct current cell of the map 
      map[i][j] = str[j];
    cout << str << endl;
  }

  // recursive search from upper-left corner
  dfs(0, 0);

  return 0;
}