运行 ID: 43938

Main.cc:2:7: error: expected nested-name-specifier before ‘namesapce’
 using namesapce std; 
       ^~~~~~~~~
Main.cc: In function ‘int main()’:
Main.cc:6:2: error: ‘cin’ was not declared in this scope
  cin >> a;
  ^~~
Main.cc:6:2: note: suggested alternative:
In file included from Main.cc:1:0:
/usr/include/c++/7/iostream:60:18: note:   ‘std::cin’
   extern istream cin;  /// Linked to standard input
                  ^~~
Main.cc:9:3: error: ‘cout’ was not declared in this scope
   cout << "positive";
   ^~~~
Main.cc:9:3: note: suggested alternative:
In file included from Main.cc:1:0:
/usr/include/c++/7/iostream:61:18: note:   ‘std::cout’
   extern ostream cout;  /// Linked to standard output
                  ^~~~
Main.cc:13:3: error: ‘cout’ was not declared in this scope
   cout << "zero";
   ^~~~
Main.cc:13:3: note: suggested alternative:
In file included from Main.cc:1:0:
/usr/include/c++/7/iostream:61:18: note:   ‘std::cout’
   extern ostream cout;  /// Linked to standard output
                  ^~~~
Main.cc:17:3: error: ‘cout’ was not declared in this scope
   cout << "negative";
   ^~~~
Main.cc:17:3: note: suggested alternative:
In file included from Main.cc:1:0:
/usr/include/c++/7/iostream:61:18: note:   ‘std::cout’
   extern ostream cout;  /// Linked to standard output
                  ^~~~