Compilare: user.cpp: In function ‘int main()’: user.cpp:122:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, x, y, w, extract, tm; ^ user.cpp:122:24: warning: unused variable ‘extract’ [-Wunused-variable] int i, j, x, y, w, extract, tm; ^ user.cpp:122:33: warning: unused variable ‘tm’ [-Wunused-variable] int i, j, x, y, w, extract, tm; ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:63:52: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, file); ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:36:48: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, file); ^