foo.cc:2:1: error: stray '##' in program
 ##include<iostream>
 ^
foo.cc:2:3: error: 'include' does not name a type
 ##include<iostream>
   ^
foo.cc:6:9: error: 'istream' does not name a type
  friend istream& operator>>(istream&, Point&);
         ^
foo.cc:7:9: error: 'ostream' does not name a type
  friend ostream& operator<<(ostream&, Point&);
         ^
foo.cc:18:1: error: 'istream' does not name a type
 istream&operator >> (istream& input, Point& p)
 ^
foo.cc:23:1: error: 'ostream' does not name a type
 ostream& operator<<(ostream& output, Point& p)
 ^
foo.cc: In function 'bool judge(Point&, Point&)':
foo.cc:30:13: error: 'abs' was not declared in this scope
  if (abs(a.x) <= 1000 && abs(a.y) <= 1000
             ^
foo.cc: In function 'int main()':
foo.cc:38:2: error: 'string' was not declared in this scope
  string s[2];
  ^
foo.cc:40:11: error: 'cin' was not declared in this scope
  while (!(cin >> a[i] >> a[i + 1]).eof())
           ^
foo.cc:45:11: error: 's' was not declared in this scope
    cin >> s[0] >> s[1];
           ^
foo.cc:56:4: error: 'cout' was not declared in this scope
    cout << a[j];
    ^
foo.cc:59:4: error: 'cout' was not declared in this scope
    cout << "Invaild input." << endl;
    ^
foo.cc:59:32: error: 'endl' was not declared in this scope
    cout << "Invaild input." << endl;
                                ^
foo.cc:39:13: warning: unused variable 'q' [-Wunused-variable]
  int i = 1, q, w;
             ^
foo.cc:39:16: warning: unused variable 'w' [-Wunused-variable]
  int i = 1, q, w;
                ^

自豪的采用 HydroJudger 进行评测(github.com/hydro-dev/HydroJudger)