# problem while playing game of fifteen

after the first move,rather than displaying a underscore(_) it is dislaying 0, and in the place of moved number it displaying a underscore and then move numbers with respect to zero.here is my code.

``````/**
* fifteen.c
*
* Computer Science 50
* Problem Set 3
*
* Implements 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 [DIM_MIN,DIM_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* Note that usleep is obsolete, but it offers more granularity than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>

// constants
#define DIM_MIN 3
#define DIM_MAX 9

// board
int board[DIM_MAX][DIM_MAX];

// dimensions
int dimen;

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

int main(int argc, string argv[])
{
// ensure proper usage
if (argc != 2)
{
printf("Usage: fifteen d\n");
return 1;
}

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

// open log
FILE* file = fopen("log.txt", "w");
if (file == NULL)
{
return 3;
}

// greet user with instructions
greet();

// initialize the board
init();

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

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

// log the current state of the board (for testing)
for (int i = 0; i < dimen; i++)
{
for (int j = 0; j < dimen; j++)
{
fprintf(file, "%i", board[i][j]);
if (j < dimen - 1)
{
fprintf(file, "|");
}
}
fprintf(file, "\n");
}
fflush(file);

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

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

// quit if user inputs 0 (for testing)
if (tile == 0)
{
break;
}

// log move (for testing)
fprintf(file, "%i\n", tile);
fflush(file);

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

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

// close log
fclose(file);

// success
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("WELCOME TO GAME OF FIFTEEN\n");
usleep(2000000);
}

/**
* Initializes the game's board with tiles numbered 1 through d*d - 1
* (i.e., fills 2D array with values but does not actually print them).
*/
void init(void)
{
// counter for assigning values to array
int tot = 1;
for ( int i = 0; i < dimen; i++)
{
for (int j = 0; j < dimen; j++)
{
// fill tiles in descending order
board[i][j] = (dimen * dimen) - tot;
tot++;
}

}
// swap 1 and 2 in case of odd no. of tiles
if ((dimen * dimen) % 2 == 0)
{
board[dimen - 1][dimen - 2] = 2;
board[dimen - 1][dimen - 3] = 1;

}
}

/**
* Prints the board in its current state.
*/
void draw(void)
{
for (int i = 0; i < dimen; i++)
{
for (int j = 0; j < dimen; j++)
{
// prints blank tile
if ( i == (dimen - 1) && j == (dimen - 1))
{
printf("%2c",'_');
}
// prints tiles in descending order
else
{
printf("%2d ",board[i][j]);
}
}
printf("\n");
}

}

/**
* If tile borders empty space, moves tile and returns true, else
* returns false.
*/
bool move(int tile)
{
for (int i = 0; i < dimen; i++)
{
for (int j = 0; j < dimen; j++)
{
if ( board[i][j] == tile)
{
// check for blank tile to the right
if ((j + 1) <= (dimen - 1) && board[i][j + 1] == 0)
{
board[i][j + 1] = tile ;
board[i][j] = 0;
return true;

}
// check for blank tile to the left
if ((j - 1) >= 0 && board[i][j - 1] == 0)
{
board[i][j - 1] = tile;
board[i][j] = 0;
return true;
}
// check for blank tile to the below
if ((i + 1) <= (dimen - 1) && board[i + 1][j] == 0)
{
board[i + 1][j] = tile ;
board[i][j] = 0;
return true;

}
// check for blank tile to the above
if ((i - 1) >= 0 && board[i - 1][j] == 0)
{
board[i - 1][j] = tile;
board[i][j] = 0;
return true;
}

}
}
}
return false;
}

/**
* Returns true if game is won (i.e., board is in winning configuration),
* else false.
*/
bool won(void)
{
int counter = 1;
if (board[dimen - 1][dimen - 1] != 0)
{
return false;

}

for (int i = 0; i < dimen; i++)
{
for (int j = 0; j < dimen; j++)
{
// check last tile if blank return true
if (i == dimen - 1 && j == dimen - 1)
{
return true;

}

// check no. on tiles
if (counter != board[i][j])
{
return false;

}

counter++;
}
}
return false;
}
``````

i am not understanding which section of code need to be change in order to get appropriate results.please help.

``````        // prints blank tile