compiler choking on mem_fun_ref()

Hello, can someone please explain the error I am getting in order to help me get my code to compile?

Code:

class RomanNumeral
{
	UINT mValue;
	vector<Symbol> mSymbols;
 
public:
	RomanNumeral(const string& romanNumeral);

	void addToSymbols(const char& c)
	{
		mSymbols.push_back(Symbol(c));
	}
};

RomanNumeral::RomanNumeral(const string& romanNumeral)
{
	for_each(romanNumeral.begin(), romanNumeral.end(), mem_fun_ref(&RomanNumeral::addToSymbols));
	sum fo = for_each(mSymbols.begin(), mSymbols.end(), sum());  // you also must check for subtraction symbols
	mValue = fo.Total;
}

The error my compiler (GCC 4.2.3) is giving:

/usr/include/c++/4.2/bits/stl_algo.h: In function ‘_Function std::for_each(_InputIterator, _InputIterator, _Function) [with _InputIterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Function = std::mem_fun1_ref_t<void, RomanNumeral, const char&>]’:
problemA.cpp:84: instantiated from here
/usr/include/c++/4.2/bits/stl_algo.h:159: error: no match for call to ‘(std::mem_fun1_ref_t<void, RomanNumeral, const char&>) (const char&)’
/usr/include/c++/4.2/bits/stl_function.h:687: note: candidates are: _Ret std::mem_fun1_ref_t<_Ret, _Tp, _Arg>:perator()(_Tp&, _Arg) const [with _Ret = void, _Tp = RomanNumeral, _Arg = const char&]

You are telling it to use a member function, but you never tell it which object you want to call it with.

Something like this might work:

Code:

for_each(romanNumeral.begin(), romanNumeral.end(), bind1st(mem_fun(&RomanNumeral::addToSymbols), this));

I also had to change the signature of the function to:

Code:

void addToSymbols(char c);