Language: C++

#include iostream
using namespace std;

int main(){
  uint64_t N;
  cin >> N;
  uint64_t multi = 1;
  bool over = false;
  for( uint64_t i = 0; i < N; ++i ){
    uint64_t tmp;
    cin >> tmp;
    
    if( tmp == 0 ){
      cout << 0 << endl;
      return 0;
    }

    multi *= tmp;
    
    if( multi > (uint64_t)1e18 || tmp > (uint64_t)1e18){
      over = true;
    }

  }

  if(over){
    cout << -1 << endl;
  }else{
    cout << fixed << setprecision(20) << multi << endl;
  }
}

Compiler output:
a.cc:1:10: error: #include expects "FILENAME" or <FILENAME>
    1 | #include iostream
      |          ^~~~~~~~
a.cc: In function 'int main()':
a.cc:5:3: error: 'uint64_t' was not declared in this scope
    5 |   uint64_t N;
      |   ^~~~~~~~
a.cc:1:1: note: 'uint64_t' is defined in header '<cstdint>'; this is probably fixable by adding '#include <cstdint>'
  +++ |+#include <cstdint>
    1 | #include iostream
a.cc:6:3: error: 'cin' was not declared in this scope
    6 |   cin >> N;
      |   ^~~
a.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
  +++ |+#include <iostream>
    1 | #include iostream
a.cc:6:10: error: 'N' was not declared in this scope
    6 |   cin >> N;
      |          ^
a.cc:7:11: error: expected ';' before 'multi'
    7 |   uint64_t multi = 1;
      |           ^~~~~~
      |           ;
a.cc:9:16: error: expected ';' before 'i'
    9 |   for( uint64_t i = 0; i < N; ++i ){
      |                ^~
      |                ;
a.cc:9:24: error: 'i' was not declared in this scope
    9 |   for( uint64_t i = 0; i < N; ++i ){
      |                        ^
a.cc:10:13: error: expected ';' before 'tmp'
   10 |     uint64_t tmp;
      |             ^~~~
      |             ;
a.cc:11:12: error: 'tmp' was not declared in this scope
   11 |     cin >> tmp;
      |            ^~~
a.cc:14:7: error: 'cout' was not declared in this scope
   14 |       cout << 0 << endl;
      |       ^~~~
a.cc:14:7: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:14:20: error: 'endl' was not declared in this scope
   14 |       cout << 0 << endl;
      |                    ^~~~
a.cc:1:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
  +++ |+#include <ostream>
    1 | #include iostream
a.cc:18:5: error: 'multi' was not declared in this scope
   18 |     multi *= tmp;
      |     ^~~~~
a.cc:20:27: error: expected ')' before numeric constant
   20 |     if( multi > (uint64_t)1e18 || tmp > (uint64_t)1e18){
      |       ~                   ^~~~
      |                           )
a.cc:27:5: error: 'cout' was not declared in this scope
   27 |     cout << -1 << endl;
      |     ^~~~
a.cc:27:5: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:27:19: error: 'endl' was not declared in this scope
   27 |     cout << -1 << endl;
      |                   ^~~~
a.cc:27:19: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
a.cc:29:5: error: 'cout' was not declared in this scope
   29 |     cout << fixed << setprecision(20) << multi << endl;
      |     ^~~~
a.cc:29:5: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:29:13: error: 'fixed' was not declared in this scope
   29 |     cout << fixed << setprecision(20) << multi << endl;
      |             ^~~~~
a.cc:1:1: note: 'std::fixed' is defined in header '<ios>'; this is probably fixable by adding '#include <ios>'
  +++ |+#include <ios>
    1 | #include iostream
a.cc:29:22: error: 'setprecision' was not declared in this scope
   29 |     cout << fixed << setprecision(20) << multi << endl;
      |                      ^~~~~~~~~~~~
a.cc:1:1: note: 'std::setprecision' is defined in header '<iomanip>'; this is probably fixable by adding '#include <iomanip>'
  +++ |+#include <iomanip>
    1 | #include iostream
a.cc:29:42: error: 'multi' was not declared in this scope
   29 |     cout << fixed << setprecision(20) << multi << endl;
      |                                          ^~~~~
a.cc:29:51: error: 'endl' was not declared in this scope
   29 |     cout << fixed << setprecision(20) << multi << endl;
      |                                                   ^~~~
a.cc:29:51: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'