View Compilation Error

0_0_38280449_28389.cpp:12:16: error: declaration of 'operator<=' as non-function
  auto operator <=> (const Point &) const = default;
                ^
0_0_38280449_28389.cpp:12:16: error: expected ';' at end of member declaration
0_0_38280449_28389.cpp:12:18: error: expected unqualified-id before '>' token
  auto operator <=> (const Point &) const = default;
                  ^
0_0_38280449_28389.cpp: In function 'int main()':
0_0_38280449_28389.cpp:44:3: error: 'sort' is not a member of 'std'
   std::sort(&p[1],&p[n*2]+1);
   ^
0_0_38280449_28389.cpp:45:15: error: 'unique' is not a member of 'std'
   const int m=std::unique(&p[1],&p[n*2]+1)-p;
               ^
0_0_38280449_28389.cpp:50:32: error: no match for 'operator==' (operand types are 'Point' and 'Point')
      if((p[i]-p[j])*(p[j]-p[k])==(Point){0,0,0}) continue;
                                ^