Xeus-cling function definition is not allowed here

If you run twice a code that defines the same variable or a function, you will encounter a compiler error, with a bad looking Red Error Message (error: redefinition of '...'). There are several ways to work around this :

Method 1: restart the compiler from scratch

select "Kernel/Restart" and re-run the different cells

MY ERROR MESSAGE:

~/workspace/pset3/fifteen/ $ make fifteen
clang -ggdb3 -O0 -std=c11 -Wall -Werror -o fifteen fifteen.c -lcs50 -lm
fifteen.c:221:1: error: function definition is not allowed here
{
^
fifteen.c:260:1: error: function definition is not allowed here
{
^
fifteen.c:281:2: error: expected '}'
}
 ^
fifteen.c:195:1: note: to match this '{'
{
^
3 errors generated.
make: *** [fifteen] Error 1

MY CODE:

#define _XOPEN_SOURCE 500

#include 
#include 
#include 
#include 

// constants
#define DIM_MIN 3
#define DIM_MAX 9

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

// dimensions
int d;

// 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
    d = atoi(argv[1]);
    if (d < DIM_MIN || d > 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 < d; i++)
        {
            for (int j = 0; j < d; j++)
            {
                fprintf(file, "%i", board[i][j]);
                if (j < d - 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(2000000);
        }

        // sleep thread for animation's sake
        usleep(2000000);
    }

    // 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)
{
    if (d % 2 != 0)
    {
        for (int i = 0; i < d; i++)
        {
            for (int j = 0; j < d; j++)
            {
                board[i][j] = d^2 - 1 - j - d*i;
            }
        }

        board[d - 1][d - 1] = 0;
        board[d - 1][d - 2] = 2;
        board[d - 1][d - 3] = 1;
    }

    else;
    {
        for (int i = 0; i < d; i++)
        {
            for (int j = 0; j < d; j++)
            {
                board[i][j] = d^2 - 1 - j - d*i;
            }
        }

        board[d - 1][d - 1] = 0;
    }
}

/**
 * Prints the board in its current state.
 */
void draw(void)
{
    for (int i = 0; i < d; i++)
    {
        for (int j = 0; j < d; j++)
        {
            if (board[i][j] <= 10)
            {
                printf(" ");

            if (board[i][j] % d == 0 && board[i][j] != 0)
            {
                printf("%i \n", board[i][j]);
            }
            else;
            {
                printf("%i   ", board[i][j]);
            }
        }
    }
}

/**
 * If tile borders empty space, moves tile and returns true, else
 * returns false. 
 */
bool move(int tile)
{
    int zeroi = d - 1;
    int zeroj = d - 1;
    for (int i = 0, i < d, i++)
    {
        for(int j = 0, j < d, j++)
        {
            if (board[i][j] == tile)
            {
                int tilei = i;
                int tilej = j;
                if ((abs(tilei - zeroi) < 2)^(abs(tilej - zeroj) < 2))
                {
                    board[zeroi][zeroj] = tile;
                    board[tilei][tilej] = 0;

                    draw();

                    return true;
                    break;  
                }
                else;
                {
                    return false;
                    break;
                }
            }
            else;
            {
                printf("Tile is not found");
                return false;
            }

        }
    }
    return false;
}

bool won(void)
{
    int count = 0;
    for (int i = 0; i < d; i++)
    {
        for(int j = 0; j < d; j++)
        {
            if (board[i][j] == j + i*d) 
            {
                count = count + 1;
            }
        }

        if (count == d*d)
        {
            return true;
        }
        else;
        {
            return false;
        }
    }
}