Question $2.[10$ points$]$

$1.$ boolean isPrime$($int n$)\{//$ tests if n is a prime number

$2.//$ Input: a positive integer n

$3.//$ Output: return true if n is a prime number, false otherwise

$4.$ for $($int x $=2$; x$*$x $<=$ n; x$++)\{$

$5.$ if $($n $\%$ x $==0)\{//$ found that x divides n

$6.$ return false;

$7.\}$

$8.\}$

$9.$ return true; $//$ found no divisor of n

$10.\}$