Compilare: user.cpp: In function ‘int main()’: user.cpp:134:12: warning: unused variable ‘top’ [-Wunused-variable] int i, top, n, j; ^ user.cpp:134:20: warning: unused variable ‘j’ [-Wunused-variable] int i, top, n, j; ^ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:17:41: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 2097152, fin); ^