Compilare: user.cpp: In function ‘int main()’: user.cpp:309:11: warning: unused variable ‘Letter1_l’ [-Wunused-variable] int Letter1_l = LetterQuery(L1 + 1); ^ user.cpp:310:11: warning: unused variable ‘Letter1_r’ [-Wunused-variable] int Letter1_r = LetterQuery(L1 + diff); ^ user.cpp:312:11: warning: unused variable ‘Letter2_l’ [-Wunused-variable] int Letter2_l = LetterQuery(L2 + 1); ^ user.cpp:313:11: warning: unused variable ‘Letter2_r’ [-Wunused-variable] int Letter2_r = LetterQuery(L2 + diff); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:60:41: 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 constructor ‘InputReader::InputReader(const char*)’: user.cpp:28:39: 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); ^