Compilare: user.cpp: In function ‘void upd(int, int, int)’: user.cpp:58:11: warning: statement has no effect [-Wunused-value] for (pos; pos <= n; pos += zero(pos)) ^ user.cpp: In function ‘int qry(int)’: user.cpp:64:11: warning: statement has no effect [-Wunused-value] for (pos; pos > 0; pos -= zero(pos)) ^ user.cpp: In function ‘void next_char()’: user.cpp:12:35: 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); ^