What is output of the following program?

#include

using namespace std;

int func$($int &x$,$ int y $=10)$

$\{$

if $($x $\%$ y $==0)$

return $++$x;

else

return y$--$;

$\}$

int main$()$

$\{$

int p $=20,$ q $=23$;

q $=$ func$($p$,$ q$)$;

cout $<<$ p $<<""<<""<<$ q $<<$ endl;

p $=$ func $($q$)$;

cout $<<$ p $<<""<<""<<$ q $<<$ endl;

q $=$ func $($p$)$;

cout $<<$ p $<<""<<""<<$ q $<<$ endl;

return $0$;

$\}$

a$.$

$2220$

$23$

$11$

b$.$

$2023$

$1023$

$1111$

c$.$

$2022$

$2310$

$1111$

d$.$

$2323$

$20$

$11$