View Compilation Error

336221_0_22550.cpp: In function `int main()':
336221_0_22550.cpp:12: error: invalid conversion from `char' to `const char*'
336221_0_22550.cpp:12: error:   initializing argument 2 of `std::basic_string<_CharT, _Traits, _Alloc>& std::basic_string<_CharT, _Traits, _Alloc>::insert(typename _Alloc::size_type, const _CharT*) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]'