Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:6:2: error: ‘cin’ was not declared in this scope cin>>a; ^~~ user.cpp:6:2: note: suggested alternative: In file included from user.cpp:1:0: /usr/include/c++/6/iostream:60:18: note: ‘std::cin’ extern istream cin; /// Linked to standard input ^~~ user.cpp:8:2: error: ‘ofstream’ was not declared in this scope ofstream o("adunare.out"); ^~~~~~~~ user.cpp:8:2: note: suggested alternative: In file included from /usr/include/c++/6/ios:38:0, from /usr/include/c++/6/ostream:38, from /usr/include/c++/6/iostream:39, from user.cpp:1: /usr/include/c++/6/iosfwd:165:34: note: ‘std::ofstream’ typedef basic_ofstream<char> ofstream; ^~~~~~~~ user.cpp:9:2: error: ‘o’ was not declared in this scope o<<a+b; ^