Why wont this code compile on gradscope?

#include

#include

#define SIZE $3$

#define EMPTY $\text{'}\text{'}$

char board$[$SIZE$][$SIZE$]$;

const char PLAYER$\_$X $=\text{'}$X$\text{'}$;

const char PLAYER$\_$O $=\text{'}$O$\text{'}$;

void resetBoard$()$;

void printBoard$()$;

int checkFreeSpaces$()$;

void playerMove$($char player$)$;

char checkWinner$()$;

void printWinner$($char winner$)$;

int main$()\{$

char winner $=$ EMPTY;

char currentPlayer $=$ PLAYER$\_$X;

resetBoard$()$;

while $($winner $==$ EMPTY && checkFreeSpaces$()!=0)\{$

printBoard$()$;

if $($currentPlayer $==$ PLAYER$\_$X$)\{$

printf$("$X$\text{'}$s turn $>")$;

$\}$ else $\{$

printf$("$O$\text{'}$s turn $>")$;

$\}$

playerMove$($currentPlayer$)$;

winner $=$ checkWinner$()$;

currentPlayer $=($currentPlayer $==$ PLAYER$\_$X$)?$ PLAYER$\_$O : PLAYER$\_$X;

$\}$

printBoard$()$;

printWinner$($winner$)$;

return $0$;

$\}$

void resetBoard$()\{$

for $($int i $=0$; i $<$ SIZE; i$++)\{$

for $($int j $=0$; j $<$ SIZE; j$++)\{$

board$[$i$][$j$]=$ EMPTY;

$\}$

$\}$

$\}$

void printBoard$()\{$

for $($int i $=0$; i $<$ SIZE; i$++)\{$

for $($int j $=0$; j $<$ SIZE; j$++)\{$

printf$("\%$c $",$ board$[$i$][$j$])$;

if $($j $<$ SIZE $-1)$ printf$("|")$;

$\}$

printf$("$

$")$;

if $($i $<$ SIZE $-1)$ printf$("---|---|---$

$")$;

$\}$

$\}$

int checkFreeSpaces$()\{$

int freeSpaces $=$ SIZE $*$ SIZE;

for $($int i $=0$; i $<$ SIZE; i$++)\{$

for $($int j $=0$; j $<$ SIZE; j$++)\{$

if $($board$[$i$][$j$]!=$ EMPTY$)\{$

freeSpaces$--$;

$\}$

$\}$

$\}$

return freeSpaces;

$\}$

void playerMove$($char player$)\{$

int x$,$ y;

while $(1)\{$

if $($scanf$("\%$d $\%$d$",$ &x$,$ &y$)!=2)\{$

fprintf$($stderr$,$ "Need $2$ co$-$ordinates

$")$;

while $($getchar$()!=\text{'}$

$\text{'})$; $//$ clear the input buffer

continue;

$\}$

if $($x $<1||$ x $>3||$ y $<1||$ y $>3)\{$

fprintf$($stderr$,"\%$d$,\%$d is not a valid square; the numbers must be between $1$ and $3$ inclusive

$",$ x$,$ y$)$;

continue;

$\}$

x$--$; y$--$; $//$ adjust for $0-$indexed array

if $($board$[$x$][$y$]!=$ EMPTY$)\{$

fprintf$($stderr$,"\%$c has played $\%$d$,\%$d

$",$ board$[$x$][$y$],$ x $+1,$ y $+1)$;

continue;

$\}$

board$[$x$][$y$]=$ player;

break;

$\}$

$\}$

char checkWinner$()\{$

$//$ Check rows and columns

for $($int i $=0$; i $<$ SIZE; i$++)\{$

if $($board$[$i$][0]!=$ EMPTY && board$[$i$][0]==$ board$[$i$][1]$ && board$[$i$][1]==$ board$[$i$][2])$ return board$[$i$][0]$;

if $($board$[0][$i$]!=$ EMPTY && board$[0][$i$]==$ board$[1][$i$]$ && board$[1][$i$]==$ board$[2][$i$])$ return board$[0][$i$]$;

$\}$

$//$ Check diagonals

if $($board$[0][0]!=$ EMPTY && board$[0][0]==$ board$[1][1]$ && board$[1][1]==$ board$[2][2])$ return board$[0][0]$;

if $($board$[0][2]!=$ EMPTY && board$[0][2]==$ board$[1][1]$ && board$[1][1]==$ board$[2][0])$ return board$[0][2]$;

return EMPTY;

$\}$

void printWinner$($char winner$)\{$

if $($winner $==$ PLAYER$\_$X$)\{$

printf$("$X wins!

$")$;

$\}$ else if $($winner $==$ PLAYER$\_$O$)\{$

printf$("$O wins!

$")$;

$\}$ else $\{$

printf$("$It$\text{'}$s a tie!

$")$;

$\}$

$\}$