foo.cpp: In function 'int main()':
foo.cpp:6:5: error: 'cin' was not declared in this scope
     cin >> a>> b;
     ^
foo.cpp:6:5: note: suggested alternative:
In file included from foo.cpp:1:0:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\iostream:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^
foo.cpp:7:5: error: 'cout' was not declared in this scope
     cout << a+b;
     ^
foo.cpp:7:5: note: suggested alternative:
In file included from foo.cpp:1:0:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^