/in/foo.cc:2:3: error: expected constructor, destructor, or type conversion before '(' token
  r(n);
   ^
/in/foo.cc:3:2: error: expected unqualified-id before 'for'
  for(re int i=1;i<=n;i++)
  ^~~
/in/foo.cc:3:17: error: 'i' does not name a type
  for(re int i=1;i<=n;i++)
                 ^
/in/foo.cc:3:22: error: 'i' does not name a type
  for(re int i=1;i<=n;i++)
                      ^
/in/foo.cc:10:2: error: 'l' does not name a type
  l=1;r=n;
  ^
/in/foo.cc:10:6: error: 'r' does not name a type
  l=1;r=n;
      ^
/in/foo.cc:11:2: error: expected unqualified-id before 'while'
  while(n)
  ^~~~~