Eroare de compilare: user.cpp:13: warning: this decimal constant is unsigned only in ISO C90 user.cpp:24: warning: this decimal constant is unsigned only in ISO C90 user.cpp: In function ‘int main()’: user.cpp:17: error: ‘ifstream’ was not declared in this scope user.cpp:17: error: expected ‘;’ before ‘f’ user.cpp:19: error: ‘f’ was not declared in this scope user.cpp:18: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result