Compilare: user.cpp: In function ‘int main()’: user.cpp:166:12: warning: variable ‘rev’ set but not used [-Wunused-but-set-variable] int n, rev, i, x, y; ^ user.cpp: In function ‘void next_char()’: user.cpp:13:35: 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, BUFF_SIZE, fin); ^