Compilare: user.cpp: In function ‘int main()’: user.cpp:46:18: warning: unused variable ‘x’ [-Wunused-variable] int i, k, n, x, l, r; ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:36:51: 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:14:47: 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); ^ user.cpp: In function ‘int main()’: user.cpp:71:19: warning: ‘r’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<l<<" "<<r<<" "<<max_base; ^ user.cpp:71:11: warning: ‘l’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<l<<" "<<r<<" "<<max_base; ^