The pseudocode below illustrates an array$-$based stack's basic push$()$ and

pop$()$ operations. If this algorithm could be used in a concurrent environment,

answer the following questions:

a$.$ What data have a race condition?

b$.$ Describe how could the race condition be fixed.

push$($item$)\{$

if $($top $<$ SIZE$)\{$

stack$[$top$]=$ item;

top$++$;

$\}$

else

ERROR

$\}$

pop$()\{$

if $(!$is$\_$empty$())\{$

top$--$;

return stack$[$top$]$;

$\}$

else

ERROR

$\}$

is$\_$empty$()\{$

if $($top $==0)$

return true;

else

return false;

$\}$