Compilare: user.cpp: In function ‘int main()’: user.cpp:14: warning: comparison between signed and unsigned integer expressions user.cpp:15: warning: array subscript has type ‘char’ user.cpp:11: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:12: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result