Não é a melhor solução, mas você pode tentar assim:
select * from srequired
where sname='C++'
UNION
select * from srequired
where sname in (select required from srequired where sname='C++')
select * from srequired
where sname='C++'
UNION
select * from srequired
where sname in (select required from srequired where sname='C++')