Compilare: user.cpp: In function ‘int solve()’: user.cpp:90:33: warning: unused variable ‘n2’ [-Wunused-variable] int answer = 1; int n1 = 0, n2 = 0; ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:29:47: 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 member function ‘void InputReader::advance()’: user.cpp:51:51: 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); ^