Segmentation fault in beginning or program

This is a discussion on Segmentation fault in beginning or program within the C Programming forums, part of the General Programming Boards category; I have got the program running but when I enter the filename of the txt file it gives me a ...

  1. #1
    Registered User
    Join Date
    Sep 2004
    Posts
    40

    Segmentation fault in beginning or program

    I have got the program running but when I enter the filename of the txt file it gives me a segmentation fault and ends.. Could someone please help me out..

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    
    #define NUMROWS 20
    #define NUMCOLS 20
    #define INFINITY 999999
    
    int read_maze(char [][], int *, int *);
    void display_maze(char [][]);
    void copy_maze(char [][], char[][]);
    void solve_maze(char [][], int, int, int);
    
    char mazeBest[NUMROWS][NUMCOLS]; /* Stores best maze found so far. */
    int lengthBest = INFINITY; /* Stores length of best maze found so far. */
    
    int main(int argc, char **argv){
        FILE *outFile = fopen("pathfile.txt", "w");
    
      char maze[NUMROWS][NUMCOLS]; /* Stores maze read from input file. */
      int startRow, startCol; /* Starting point in maze. */
      if (read_maze(maze, &startRow, &startCol) == 0)
        {
          printf("Error reading maze from file robotfile.txt!\n");
          return;
        }
    
      printf("Starting maze:\n");
      display_maze(maze);
      solve_maze(maze, startRow, startCol, 0);
      if (lengthBest == INFINITY)
        {
          printf("\nNo path to goal was found in maze!\n");
          return;
        }
      else
        {
          printf("\nBest solution found:\n");
          display_maze(mazeBest);
       }
    
      return;
    }
    
    /*
     * Read maze from "robotfile.txt".
     * Fill in *sRow and *sCol with position of 'O'.
     * If error, return 0, else return 1.
     */
    int read_maze(char maze[NUMROWS][NUMCOLS], int *sRow, int *sCol)
    {
          char filename;
          printf("Enter the name of the maze file. \n");
          scanf("%s", filename);
          FILE *inFile = fopen("filename", "r");
          int row, col;
    
      /* Open maze text file, make sure it opens OK. */
      if ((inFile = fopen("robotfile.txt", "r")) == NULL)
    {
          char filename;
          printf("Enter the name of the maze file. \n");
          scanf("%s", filename);
          FILE *inFile = fopen("filename", "r");
          int row, col;
    
      /* Open maze text file, make sure it opens OK. */
      if ((inFile = fopen("robotfile.txt", "r")) == NULL)
        return 0;
    
      /* Loop through the rows. */
      for (row = 0; row < NUMROWS; row++)
        {
          /* Loop through the column in current row. */
          for (col = 0; col < NUMROWS; col++)
            {
              maze[row][col] = getc(inFile);
              /* Check if this is the starting position. */
      if (maze[row][col] == 'O')
                {
                  *sRow = row;
                  *sCol = col;
                }
            }
          /* Ignore newline at end of each row. */
          getc(inFile);
        }
             fclose(inFile);
    
      return 1;
    }
    
    /* Display the maze passed as a parameter to standard output. */
    void display_maze(char maze[NUMROWS][NUMCOLS])
    {
      int row, col;
      for (row = 0; row < NUMROWS; row++)
        {
          for (col = 0; col < NUMCOLS; col++)
            {
              putchar(maze[row][col]);
            }
          putchar('\n');
        }
    
      return;
    }
    
    /* Copy the maze in mazeSrc to mazeDest. */
    void copy_maze(char mazeSrc[NUMROWS][NUMCOLS],
                   char mazeDest[NUMROWS][NUMCOLS])
    {
      int row, col;
    
      for (row = 0; row < NUMROWS; row++)
        {
     for (col = 0; col < NUMCOLS; col++)
            {
              mazeDest[row][col] = mazeSrc[row][col];
            }
        }
    
      return;
    }
    
    /*
     * Given:
     *    (1) maze with path so far
     *    (2) current row
     *    (3) current column
     *    (4) length of path so far
     * The function solve_maze recursively tries to solve the maze.
     *
     * When a solution is found, compare it to previous best found solution,
     * and update appropriate globals if necessary.
     */
    void solve_maze(char mazeCur[NUMROWS][NUMCOLS], int curRow, int curCol,
    int length)
    {
      /* If already as long as best solution, no need to look further. */
      if (length >= lengthBest)
        return;
    
      /* Check if solution found. */
      if ((mazeCur[curRow-1][curCol] == 'X') ||
          (mazeCur[curRow+1][curCol] == 'X') ||
         (mazeCur[curRow][curCol+1] == 'X') ||
          (mazeCur[curRow][curCol-1] == 'X'))
        {
          /* Found solution, better then previous best, update globals. */
          lengthBest = length;
          copy_maze(mazeCur, mazeBest);
          return;
        }
    
      /* Recurse in each possible direction that is empty. */
      if (mazeCur[curRow-1][curCol] == ' ')
        {
          mazeCur[curRow-1][curCol] = 'O';
          solve_maze(mazeCur, curRow-1, curCol, length+1);
          mazeCur[curRow-1][curCol] = ' ';
        }
      if (mazeCur[curRow+1][curCol] == ' ')
        {
          mazeCur[curRow+1][curCol] = 'O';
          solve_maze(mazeCur, curRow+1, curCol, length+1);
         mazeCur[curRow+1][curCol] = ' ';
        }
      if (mazeCur[curRow][curCol-1] == ' ')
        {
          mazeCur[curRow][curCol-1] = 'O';
          solve_maze(mazeCur, curRow, curCol-1, length+1);
          mazeCur[curRow][curCol-1] = ' ';
        }
      if (mazeCur[curRow][curCol+1] == ' ')
        {
         mazeCur[curRow][curCol+1] = 'O';
          solve_maze(mazeCur, curRow, curCol+1, length+1);
          mazeCur[curRow][curCol+1] = ' ';
        }
    
      return;
    }

  2. #2
    ---
    Join Date
    May 2004
    Posts
    1,379
    Code:
          char filename;
          printf("Enter the name of the maze file. \n");
          scanf("%s", filename);
          FILE *inFile = fopen("filename", "r");
    char filename; is only enough space for a single character. And dont use scanf to input strings.
    You need to use fgets()
    Code:
    #include <stdio.h>
    #define SIZE 15
    
    int main(void)
    {
      char filename[SIZE];
      fgets(filename,SIZE,stdin);
      return 0;
    }
    Last edited by sand_man; 02-26-2005 at 07:18 PM.

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