Eroare de compilare: user.cpp: In function 'int main()': user.cpp:8: error: 'ifstream' was not declared in this scope user.cpp:8: error: expected `;' before 'o' user.cpp:9: error: 'ofstream' was not declared in this scope user.cpp:9: error: expected `;' before 'p' user.cpp:10: error: 'o' was not declared in this scope user.cpp:20: error: 'sort' was not declared in this scope user.cpp:42: error: 'p' was not declared in this scope user.cpp:44: error: 'p' was not declared in this scope