Jeff 15 puzzle

gistfile1.c

/**
 * fifteen.c
 *
 * Computer Science 50
 * Problem Set 3
 *
 * Implements the Game of Fifteen (generalized to d x d).
 *
 * Usage: ./fifteen d
 *
 * whereby the board's dimensions are to be d x d,
 * where d must be in [MIN,MAX]
 *
 * Note that usleep is obsolete, but it offers more granularity than
 * sleep and is simpler to use than nanosleep; `man usleep` for more.
 */
 
#define _XOPEN_SOURCE 500

#include <cs50.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>

// board's minimal dimension
#define MIN 3

// board's maximal dimension
#define MAX 9

// board, whereby board[i][j] represents row i and column j
int board[MAX][MAX];

// board's dimension
int d;

// prototypes
void clear(void);
void greet(void);
void init(void);
void draw(void);
bool move(int tile);
bool won(void);
void save(void);

int main(int argc, string argv[])
{
    // greet player
    greet();

    // ensure proper usage
    if (argc != 2)
    {
        printf("Usage: ./fifteen d\n");
        return 1;
    }

    // ensure valid dimensions
    d = atoi(argv[1]);
    if (d < MIN || d > MAX)
    {
        printf("Board must be between %i x %i and %i x %i, inclusive.\n",
            MIN, MIN, MAX, MAX);
        return 2;
    }

    // initialize the board
    init();

    // accept moves until game is won
    while (true)
    {
        // clear the screen
        clear();

        // draw the current state of the board
        draw();

        // saves the current state of the board (for testing)
        save();

        // check for win
        if (won())
        {
            printf("ftw!\n");
            break;
        }

        // prompt for move
        printf("Tile to move: ");
        int tile = GetInt();

        // move if possible, else report illegality
        if (!move(tile))
        {
            printf("\nIllegal move.\n");
            usleep(500000);
        }

        // sleep for animation's sake
        usleep(500000);
    }

    // that's all folks
    return 0;
}

/**
 * Clears screen using ANSI escape sequences.
 */
void clear(void)
{
    printf("\033[2J");
    printf("\033[%d;%dH", 0, 0);
}

/**
 * Greets player.
 */
void greet(void)
{
    clear();
    printf("GAME OF FIFTEEN\n");
    usleep(2000000);
}

/**
 * Initializes the game's board with tiles numbered 1 through d*d - 1,
 * (i.e., fills board with values but does not actually print them),
 * whereby board[i][j] represents row i and column j.
 */
void init(void)
{
    // TODO
    for (int i = 0; i < d; i++) {
        for (int j = 0; j < d; j++) {
                board[i][j] = d*d - (j + (i*d)+1);
                if (board[i][j] == 0) {
                    board[i][j] = d*d;
                }
                //printf("board[%d][%d] = %d \n", i, j, board[i][j]);
            }
        }
}

/**
 * Prints the board in its current state.
 */
void draw(void)
{
    // TODO
    //for each row
    for (int i = 0; i < d; i++) {
    
        //for each value in row
        for (int j = 0; j < d; j++) {
        
            //print value and space
            if (board[i][j] == d*d) {
                printf(" _ ");
            }
            else {
            printf("%2d ", board[i][j]);
            }
        }           
        //print new line
        printf("\n");
    }
}

/**
 * If tile borders empty space, moves tile and returns true, else
 * returns false. 
 */
bool move(int tile)
{
    // TODO
    //find location of blank tile
    int btrow;
    int btcolumn;
    for (int i = 0; i < d; i++) {
        for (int j = 0; j < d; j++) {
            if (board[i][j] == d*d) {
                btrow = i;
                btcolumn = j;
            }
        }
    }
    
    //find location of usertile
    int utrow;
    int utcolumn;
    for (int i = 0; i < d; i++) {
        for (int j = 0; j < d; j++) {
            if (board[i][j] == tile) {
                utrow = i;
                utcolumn = j;
            }
        }
    }   
    //check if both row and col differ
    if (btrow != utrow && btcolumn != utcolumn) {
        return false;
    }
    //check if difference between elements is greater than 1
    if (btrow == utrow || btcolumn == utcolumn) {
        int a = (btrow + btcolumn) - (utrow + utcolumn);
        int b = abs(a);        

        if (b > 1) {
            return false;
        }
    
    //swap usertile and blanktile
        else {
        int* x = &board[btrow][btcolumn];
        int* y = &board[utrow][utcolumn];
        int tmp = *x;
        *x = *y;
        *y = tmp;
        board[btrow][btcolumn] = *x;
        board[utrow][utcolumn] = *y;
        }   
    //return true
        return true;
    }
    return false;
}

/**
 * Returns true if game is won (i.e., board is in winning configuration), 
 * else false.
 */
bool won(void)
{
        //for each row
    int reqnum = 1;
    for (int i = 0; i < d; i++) {
    
        //for each value in row
        for (int j = 0; j < d; j++) {
            if (board[i][j] != reqnum)  {
            return false;
            }
        reqnum++;
        }
    }
return true;
}
/**
 * Saves the current state of the board to disk (for testing).
 */
void save(void)
{
    // log
    const string log = "log.txt";

    // delete existing log, if any, before first save
    static bool saved = false;
    if (!saved)
    {
        unlink(log);
        saved = true;
    }

    // open log
    FILE* p = fopen(log, "a");
    if (p == NULL)
    {
        return;
    }

    // log board
    fprintf(p, "{");
    for (int i = 0; i < d; i++)
    {
        fprintf(p, "{");
        for (int j = 0; j < d; j++)
        {
            fprintf(p, "%i", board[i][j]);
            if (j < d - 1)
            {
                fprintf(p, ",");
            }
        }
        fprintf(p, "}");
        if (i < d - 1)
        {
            fprintf(p, ",");
        }
    }
    fprintf(p, "}\n");

    // close log
    fclose(p);
}