View Compilation Error

0_0_2511704_22239.cpp:4: error: `main' must return `int'
0_0_2511704_22239.cpp: In function `int main(...)':
0_0_2511704_22239.cpp:6: error: no match for 'operator!=' in '(&std::cin)->std::basic_istream<_CharT, _Traits>::operator>> [with _CharT = char, _Traits = std::char_traits<char>](((double&)(&x))) != -0x000000001'