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| Game Application Using C |
MAIN.C
======
Main function for maze solver
*/
#include
#include
#include "maze.h"
#include "solve.h"
int main(int argc, char *argv[]) {
struct maze maze;
if ( argc < 2 ) {
puts("You must specify the filename of your maze");
return EXIT_FAILURE;
}
else if ( argc > 2 ) {
puts("Too many command line arguments");
return EXIT_FAILURE;
}
GetMazeFromFile(argv[1], &maze);
if ( solve(&maze) == MAZE_FOUNDEXIT )
puts("Found exit!");
else
puts("Can't reach exit!");
PrintMaze(&maze);
FreeMaze(&maze);
return EXIT_SUCCESS;
}
--------------------------------------------------------------------------------
maze.h
/*
MAZE.H
======
Interface to maze functions
*/
#ifndef PG_MAZE_H
#define PG_MAZE_H
/* Structure definitions */
struct maze {
char ** map;
int startx, starty;
int numrows;
int initdir;
};
struct pos {
int x, y, dir;
};
/* Macros */
#define BUFFERSIZE (1000)
#define MAZE_ENTRANCE 'I'
#define MAZE_EXIT 'O'
#define MAZE_WALL 'X'
#define MAZE_PATH ' '
#define MAZE_TRAIL '@'
#define MOVE_LEFT (0)
#define MOVE_UP (1)
#define MOVE_RIGHT (2)
#define MOVE_DOWN (3)
#define MAZE_NOWAY (0)
#define MAZE_FOUNDEXIT (1)
#define MAZE_NOEXIT (-1)
/* Function declarations */
void GetMazeFromFile(char * filename, struct maze * maze);
void FreeMaze(struct maze * maze);
void PrintMaze(struct maze * maze);
#endif /* PG_MAZE_H */
--------------------------------------------------------------------------------
maze.c
/*
MAZE.C
======
Implementation of maze functions
*/
#include
#include
#include
#include
#include "maze.h"
/* Creates a maze from a file */
void GetMazeFromFile(char * filename, struct maze * maze) {
char buffer[BUFFERSIZE];
FILE * fp;
char ** map;
int n = 0, foundentrance = 0, foundexit = 0;
/* Open file */
if ( !(fp = fopen(filename, "r")) ) {
sprintf(buffer, "Couldn't open file %s", filename);
perror(buffer);
exit(EXIT_FAILURE);
}
/* Determine number of rows in maze */
while ( fgets(buffer, BUFFERSIZE, fp) )
++n;
/* Allocate correct number of rows */
if ( !(map = malloc(n * sizeof *map)) ) {
fputs("Couldn't allocate memory for map\n", stderr);
exit(EXIT_FAILURE);
}
/* Reset file */
rewind(fp);
n = 0;
/* Store each row */
while ( fgets(buffer, BUFFERSIZE, fp) ) {
int i;
if ( !(map[n] = malloc((strlen(buffer)+1) * sizeof map[n])) ) {
fputs("Couldn't allocate memory for map\n", stderr);
for ( i = 0; i < n; ++i )
free(map[i]);
free(map);
exit(EXIT_FAILURE);
}
strcpy(map[n], buffer);
/* Remove trailing whitespace */
for ( i = strlen(map[n]) - 1; isspace(map[n][i]); --i )
map[n][i] = 0;
/* Check for entrance and store position if found */
if ( !foundentrance ) {
i = 0;
while ( map[n][i] != 'I' && map[n][i++] );
if ( map[n][i] == MAZE_ENTRANCE ) {
maze->startx = i;
maze->starty = n;
foundentrance = 1;
}
}
/* Check for exit */
if ( !foundexit ) {
if ( strchr(map[n], MAZE_EXIT) )
foundexit = 1;
}
++n;
}
/* Fill in maze structure */
maze->map = map;
maze->numrows = n;
/* Exit if there is no entrance or no exit */
if ( !foundentrance ) {
fputs("Maze has no entrance!\n", stderr);
FreeMaze(maze);
exit(EXIT_FAILURE);
}
if ( !foundexit ) {
fputs("Maze has no exit!\n", stderr);
FreeMaze(maze);
exit(EXIT_FAILURE);
}
/* Check for initial direction into the maze */
if ( maze->startx < strlen(maze->map[maze->starty]) - 1 &&
maze->map[maze->starty][maze->startx+1] == MAZE_PATH )
maze->initdir = MOVE_RIGHT;
else if ( maze->startx > 0 &&
maze->map[maze->starty][maze->startx-1] == MAZE_PATH )
maze->initdir = MOVE_LEFT;
else if ( maze->starty > 0 &&
maze->map[maze->starty-1][maze->startx] == MAZE_PATH )
maze->initdir = MOVE_UP;
else if ( maze->starty < (maze->numrows-1) &&
maze->map[maze->starty+1][maze->startx] == MAZE_PATH )
maze->initdir = MOVE_DOWN;
/* Close file and return */
if ( fclose(fp) ) {
perror("Couldn't close file");
FreeMaze(maze);
exit(EXIT_FAILURE);
}
}
/* Frees memory used by a maze */
void FreeMaze(struct maze * maze) {
int n;
for ( n = 0; n < maze->numrows; ++n )
free(maze->map[n]);
free(maze->map);
}
/* Outputs a maze */
void PrintMaze(struct maze * maze) {
int n;
for ( n = 0; n < maze->numrows; ++n )
puts(maze->map[n]);
}
--------------------------------------------------------------------------------
solve.h
/*
SOLVE.H
=======
Interface to maze solving operation
*/
#ifndef PG_SOLVE_H
#define PG_SOLVE_H
#include "maze.h"
/* Function declarations */
int solve(struct maze * maze);
#endif /* PG_SOLVE_H */
--------------------------------------------------------------------------------
solve.c
/*
SOLVE.C
=======
Implementation of maze solving operation
*/
#include "solve.h"
/* Recursive function to find a path through a maze */
int look(struct maze * maze, struct pos pos) {
int i, n;
/* Set new position based on direction */
switch ( pos.dir ) {
case MOVE_UP:
pos.y -= 1;
break;
case MOVE_DOWN:
pos.y += 1;
break;
case MOVE_LEFT:
pos.x -= 1;
break;
case MOVE_RIGHT:
pos.x += 1;
break;
default:
break;
}
/* Check new position */
if ( pos.y < 0 || pos.y >= maze->numrows )
return MAZE_NOWAY;
else if ( pos.x < 0 || pos.x >= strlen(maze->map[pos.y]) )
return MAZE_NOWAY;
else if ( maze->map[pos.y][pos.x] == MAZE_WALL )
return MAZE_NOWAY;
else if ( maze->map[pos.y][pos.x] == MAZE_EXIT )
return MAZE_FOUNDEXIT;
else if ( maze->map[pos.y][pos.x] == MAZE_ENTRANCE )
return MAZE_NOEXIT;
/* Try all the three directions other than backwards */
pos.dir -= 1;
if ( pos.dir < 0 )
pos.dir += 4;
for ( i = 0; i < 3; ++i ) {
maze->map[pos.y][pos.x] = MAZE_TRAIL; /* Leave trail through maze */
n = look(maze, pos);
if ( n ) {
if ( n == MAZE_NOEXIT )
maze->map[pos.y][pos.x] = MAZE_PATH; /* No exit, so clear trail */
return n;
}
pos.dir += 1;
if ( pos.dir > 3 )
pos.dir -= 4;
}
/* Dead end, so clear trail and return */
maze->map[pos.y][pos.x] = MAZE_PATH;
return 0;
}
/* Function to find a path through a maze */
int solve(struct maze * maze) {
struct pos pos;
pos.x = maze->startx;
pos.y = maze->starty;
pos.dir = maze->initdir;
return look(maze, pos);
}
Sample Output :
--------------------------------------------------------------------------------
maze1.maz
XXXXXXXXXXXXXXXIXXX
X X
X XXXXXXXXXXXXXXXXX
X X X
X XXX XXXXX X X X X
X X X X X X X X
X X X XXX X X X X X
X X X X X X X
XXXXXXXXXXXOXXXXXXX
--------------------------------------------------------------------------------
maze2.maz
XXXXXXXXXXXXXXXXXXXX
X X X X
X X XXXX XXX XXXXXXX
X X X X
X X X XXXXX XXX X XX
X XXX X X X X X XX
I X X X XXXXXX
X XXXXX X X X
X X X X XX O
XXXXXXXXXXXXXXXXXXXX
--------------------------------------------------------------------------------
nowayout.maz
XXXXXXXXXIXXXXXXXXX
X X XX XX X X
X X X X X X
X XXXXX X X XXXXX X
X O X
X XXXXX X X XXXXX X
X X X X X X
X X XX XX X X
XXXXXXXXXXXXXXXXXXX
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