Which line in the following program will cause a compiler error?

$1$ Hiclude kiostream?

$2$ using namespace std;

$3$

$4$ int main $()$

$5^4$

int number $=5$;

If $($number $=0$ cs $=100)$

cout $$ passed. Nn$"$;

else

cout $$ failed.,$n$

return $0$;