Compilare: main.cpp: In function 'void smart(int, int, int)': main.cpp:113:9: warning: unused variable 'l' [-Wunused-variable] int l = sqrt(m); ^ main.cpp: In constructor 'InputReader::InputReader(const char*)': main.cpp:45:43: 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); ^ main.cpp: In member function 'void InputReader::advance()': main.cpp:73:47: 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); ^