View Compilation Error

0_0_34031262_26084.cpp: In function 'int main()':
0_0_34031262_26084.cpp:50:18: error: cannot bind 'std::istream {aka std::basic_istream<char>}' lvalue to 'std::basic_istream<char>&&'
             cin>>a;
                  ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:40:0,
                 from 0_0_34031262_26084.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/istream:872:5: note: initializing argument 1 of 'std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&&, _Tp&) [with _CharT = char; _Traits = std::char_traits<char>; _Tp = double [55]]'
     operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x)
     ^
0_0_34031262_26084.cpp:51:32: error: invalid operands of types '__gnu_cxx::__promote_2<double, int, double, double>::__type {aka double}' and 'double [55]' to binary 'operator*'
             sum+=pow(0.95,i-1)*a;
                                ^