Compilare: user.cpp: In function ‘int main()’: user.cpp:111:18: warning: unused variable ‘c’ [-Wunused-variable] int n, l, u, c, dr; ^ user.cpp:111:21: warning: unused variable ‘dr’ [-Wunused-variable] int n, l, u, c, dr; ^ user.cpp:112:9: warning: variable ‘ans’ set but not used [-Wunused-but-set-variable] i64 ans; ^ user.cpp: In constructor ‘furt_reader::furt_reader(const char*)’: user.cpp:29:43: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In member function ‘void furt_reader::advance()’: user.cpp:18:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^