C Programming: Maze Solver for Introductory Programming Course

This C program implements a maze solver, designed to navigate a maze represented by a 2D array. The program reads maze configurations from a file, where different characters denote walls, the player's starting position, keys, and the exit. It includes functions for reading the maze from a file, printing the maze, moving the player, checking for completion, and 'looking' at adjacent cells. The code manages key collection, preventing movement to the exit without the required number of keys. Error handling is implemented to manage invalid inputs such as multiple players or exits, out-of-bounds movements, and diagonal moves. The program uses functions such as `readMaze`, `printMaze`, `move`, `look`, `getCurrentKeys`, `getTotalKeys`, and `isComplete` to implement the maze's functionality. The `move` function handles player movement and key collection, while the `look` function provides information about the contents of a cell. The program keeps track of the number of steps taken and the number of keys collected during the maze traversal.

#include "Maze.h"
static int mazeStructure[500][500] = { 0 };
static int numTotalKeys = 0;
static int numKeysHeld = 0;
static int maxRow = 0;
static int maxCol = 0;
static int playerRow = -1;
static int playerCol = -1;
static int exitRow = -1;
static int exitCol = -1;
static int readMazeRan = 0;
static int numSteps = 0;
int getCurrentKeys(){
return numKeysHeld;
}
int getTotalKeys(){
return numTotalKeys;
}
int getNumSteps(){
return numSteps;
}
void getCurrentPosition(int * arr){
arr[0] = playerRow;
arr[1] = playerCol;
}
int abs(int x){
if (x < 0) return 0-x;
return x;
}
int dangerous(int x, int y){
return x < 0 || y < 0 || x >= 500 || y >= 500;
}
//fills the maze based on the file given
void readMaze(char* fileName){
if(readMazeRan){
printf("ERROR: Multiple calls to readMaze\n");
return;
}
readMazeRan = 1;
//stuff too complicated to cover in class
FILE *inputFile = fopen(fileName, "r");
char currentChar;
int currentRow = 0;
int currentCol = 0;
while((currentChar = fgetc(inputFile)) != EOF){
if(currentChar == '\n'){
if(currentCol > maxCol){

maxCol = currentCol;
}
currentRow += 1;
currentCol = 0;
} else {
//3 is a key
if(currentChar == '3'){
numTotalKeys++;
//2 is a player, but only one is allowed
}else if(currentChar == '2'){
if(playerRow != -1){
printf("ERROR: You can't have more than one player! The instance at
(%d, %d) was ignored in favor of the instance at (%d, %d).\n", currentRow,
currentCol, playerRow, playerCol);
currentChar = '1';
}else{
playerRow = currentRow;
playerCol = currentCol;
}
//4 is an exit, but only one is allowed
}else if(currentChar == '4'){
if(exitRow != -1){
printf("ERROR: You can't have more than one exit! The instance at
(%d, %d) was ignored in favor of the instance at (%d, %d).\n", currentRow,
currentCol, exitRow, exitCol);
currentChar = '1';
}else{
exitRow = currentRow;
exitCol = currentCol;
}
}
if(currentChar >= '0' && currentChar <= '4'){
mazeStructure[currentRow][currentCol] = currentChar - 48;
}else{
printf("ERROR: Unrecognized character at (%d, %d)\n", currentRow,
currentCol);
}
currentCol+=1;
}
}
if(playerRow == -1){
printf("ERROR: No player object was found\n");
}
if(exitRow == -1){
printf("ERROR: No exit object was found\n");
}
maxRow = currentRow;
}
void printMaze(){

int i,j;
for(i=0; i<maxRow; i++){
for(j=0; j<maxCol; j++){
printf("%d", mazeStructure[i][j]);
}
printf("\n");
}
for(i=0;i<maxCol;i++){
printf("-");
}
printf("\n");
}
int isComplete(){
return playerRow == exitRow && playerCol == exitCol;
}
int move(int newRow, int newCol){
if(dangerous(newRow, newCol)){
printf("Out of bounds\n");
return 0;
}
if(playerRow == newRow && playerCol == newCol){
printf("You are already at (%d, %d).\n", newRow, newCol);
return 0;
}
if(abs(playerRow - newRow) == 1 && abs(playerCol - newCol) == 1){
printf("You tried to move to (%d, %d), but that requires moving
diagonally, which is not allowed!\n", newRow, newCol);
return 0;
}
if(abs(playerRow - newRow) > 1 || abs(playerCol - newCol) > 1){
printf("You tried to move to (%d, %d), but that is more than one square
away!\n", newRow, newCol);
return 0;
}
if(mazeStructure[newRow][newCol] == 0){
printf("You tried to move to (%d, %d), but there is a wall in the way!\n",
newRow, newCol);
return 0;
}
if(mazeStructure[newRow][newCol] == 4 && numKeysHeld < numTotalKeys){
printf("The exit is at (%d, %d), but you only have %d/%d keys!\n", newRow,
newCol, numKeysHeld, numTotalKeys);
return 0;
}
if(mazeStructure[newRow][newCol] == 3){
printf("Congratulations! You have found a key! You now have %d/%d keys!\
n", ++numKeysHeld, numTotalKeys);
mazeStructure[newRow][newCol] = 1;
}

mazeStructure[playerRow][playerCol] = 1;
mazeStructure[newRow][newCol] = 2;
numSteps++;
playerRow = newRow;
playerCol = newCol;
return 1;
}
int look(int newRow, int newCol){
if(dangerous(newRow, newCol)){
printf("Out of bounds\n");
return 0;
}
if(abs(playerRow - newRow) == 1 && abs(playerCol - newCol) == 1){
printf("You tried to look at (%d, %d), but that requires looking
diagonally, which is not allowed!\n", newRow, newCol);
return -1;
}
if(abs(playerRow - newRow) > 1 || abs(playerCol - newCol) > 1){
printf("You tried to look at (%d, %d), but that is more than one square
away!\n", newRow, newCol);
return -1;
}
switch(mazeStructure[newRow][newCol]){
case 0:
printf("That's a wall.\n");
break;
case 1:
printf("There's nothing there.\n");
break;
case 2:
printf("You take a long hard look at yourself.\n");
break;
case 3:
printf("That's a key! Pick it up!\n");
break;
case 4:
printf("That's the exit! Do you have enough keys?\n");
break;
default:
printf("Not sure what that is.\n");
break;
}
return mazeStructure[newRow][newCol];
}