why does my code still have $4$ errors in the $($int main$)$ section and will not run in eclipse?

#include

#include

using namespace std;

void countUp$()\{$

int i;

for$($i $=0$; i $<=20$; i$++)\{$

cout $<<$ i $<<$ endl;

$\}$

$\}$

void countDown$()\{$

int i;

for$($i $=19$; i $>=0$; i$--)\{$

cout $<<$ i $<<$ endl;

$\}$

$\}$

int main$()\{$

thread countUpThread$($countUp$)$;

countUpThread.join$()$;

thread countDownThread$($countDown$)$;

countDownThread.join$()$;

return $0$;

$\}$

here are the errors that I keep getting

$..\backslash$src$\backslash$Module$7$Porfolio.cpp:$27$:$4$: error: 'thread' was not declared in this scope

thread countUpThread$($countUp$)$;

$^$~~~~~

$..\backslash$src$\backslash$Module$7$Porfolio.cpp:$28$:$4$: error: 'countUpThread' was not declared in this scope

countUpThread.join$()$;

$^$~~~~~~~~~~~~

$..\backslash$src$\backslash$Module$7$Porfolio.cpp:$29$:$11$: error: expected $\text{'}$;$\text{'}$ before 'countDownThread'

thread countDownThread$($countDown$)$;

$^$~~~~~~~~~~~~~~

$..\backslash$src$\backslash$Module$7$Porfolio.cpp:$30$:$4$: error: 'countDownThread' was not declared in this scope

countDownThread.join$()$;

$^$~~~~~~~~~~~~~~

$14$:$50$:$14$ Build Failed. $4$ errors, $0$ warnings. $($took $826$ms$)$