Eroare de compilare: user.cpp:1:21: error: iostream.h: No such file or directory user.cpp:2:20: error: fstream.h: No such file or directory user.cpp: In function ‘int main()’: user.cpp:6: error: ‘ifstream’ was not declared in this scope user.cpp:6: error: expected ‘;’ before ‘in’ user.cpp:7: error: ‘ofstream’ was not declared in this scope user.cpp:7: error: expected ‘;’ before ‘out’ user.cpp:9: error: ‘in’ was not declared in this scope user.cpp:19: error: ‘out’ was not declared in this scope user.cpp:67: error: ‘abs’ was not declared in this scope user.cpp:72: error: ‘abs’ was not declared in this scope user.cpp:85: error: ‘abs’ was not declared in this scope user.cpp:93: error: ‘abs’ was not declared in this scope user.cpp:8: warning: unused variable ‘a’