/in/foo.cc:4:16: error: expected unqualified-id before ')' token
 struct student(){
                ^
/in/foo.cc: In function 'bool cmp(student, student)':
/in/foo.cc:9:18: error: 'a' has incomplete type
 bool cmp(student a,student b){
                  ^
/in/foo.cc:4:8: note: forward declaration of 'struct student'
 struct student(){
        ^~~~~~~
/in/foo.cc:9:28: error: 'b' has incomplete type
 bool cmp(student a,student b){
                            ^
/in/foo.cc:4:8: note: forward declaration of 'struct student'
 struct student(){
        ^~~~~~~
/in/foo.cc:10:17: error: expected primary-expression before 'a'
  return student a.money<student b.money;
                 ^
/in/foo.cc:10:17: error: expected ';' before 'a'
/in/foo.cc:10:33: error: expected primary-expression before 'b'
  return student a.money<student b.money;
                                 ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:15:14: error: elements of array 'student s [sn]' have incomplete type
  student s[sn];
              ^
/in/foo.cc:15:14: error: storage size of 's' isn't known