src.cpp: In function 'int main()':
src.cpp:44:12: error: no 'operator++(int)' declared for postfix '++' [-fpermissive]
dem++;
^
src.cpp:46:11: error: cannot bind 'std::ostream {aka std::basic_ostream<char>}' lvalue to 'std::basic_ostream<char>&&'
cout<<dem;
^
In file included from C:/Debug/compiler/gcc/lib/gcc/mingw32/4.9.2/include/c++/istream:39:0,
from C:/Debug/compiler/gcc/lib/gcc/mingw32/4.9.2/include/c++/sstream:38,
from C:/Debug/compiler/gcc/lib/gcc/mingw32/4.9.2/include/c++/complex:45,
from C:/Debug/compiler/gcc/lib/gcc/mingw32/4.9.2/include/c++/ccomplex:38,
from C:/Debug/compiler/gcc/lib/gcc/mingw32/4.9.2/include/c++/mingw32/bits/stdc++.h:52,
from src.cpp:1:
C:/Debug/compiler/gcc/lib/gcc/mingw32/4.9.2/include/c++/ostream:602:5: note: initializing argument 1 of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&&, const _Tp&) [with _CharT = char; _Traits = std::char_traits<char>; _Tp = std::vector<int>]'
operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x)
^