Eroare de compilare: user.cpp:1:20: error: fstream.h: No such file or directory user.cpp:2: error: ‘ifstream’ does not name a type user.cpp:2: error: ‘ofstream’ does not name a type user.cpp: In function ‘void back()’: user.cpp:13: error: ‘g’ was not declared in this scope user.cpp:13: error: ‘g’ was not declared in this scope user.cpp:12: warning: suggest explicit braces to avoid ambiguous ‘else’ user.cpp: In function ‘int main()’: user.cpp:20: error: ‘f’ was not declared in this scope user.cpp:22: error: ‘g’ was not declared in this scope