I made a histogram class and wanted to test it, but I'm getting errors like this:

Code:
303 C:\Dev-Cpp\Projects\Histography\main.cpp   instantiated from here
which is this line:
cout << hist.get_most_num_occurances();

Code:
101 C:\Dev-Cpp\Projects\Histography\main.cpp 'struct std::_Rb_tree_iterator<std::pair<const char, int> >' has no member named 'begin'
Not sure.


The main method looks like this:
Code:
int main()
{
   map<char, int> my_map;
   my_map.insert( make_pair('a',2) );
   my_map.insert( make_pair('b',3) );
   my_map.insert( make_pair('c',1) );
   
   Histogram<char> hist(my_map);
   
   cout << hist.get_most_num_occurances();
   getchar();
}
The bold line is what gives the error.

This is the function:

Code:
template <typename T> int Histogram<T>::get_most_num_occurances()
{
         typename map<T,int>::iterator ci;
         int high = ci.begin();
         
         for (ci=frequency.begin(); ci != frequency.end(); ++ci)
         {
             if (ci->second > high)
             {
                high = ci->second;
             }
         }
}

Can anyone spot the problem? I've been beating my head on this one and can't figure it out.