Problem with wring my own iterator

Hi everyone

I tried to copied the code of some program that uses their own
iterator to loop over some elements of map... The code seems simple
and works in the program I copied it from of course (and I can compile
it) but I can get my own version to work. I get this error message:

xx.cc: In member function =91A::Iterator A::begin()':
xx.cc:716: error: conversion from
=91std::_Rb_tree_iterator<std::pair<const std::basic_string<char,
std::char_traits<char>, std::allocator<char> >, int> >' to non-scalar
type =91A::Iterator' requested
xx.cc: In member function =91int& A::Iterator::value() const':
xx.cc:737: error: invalid initialization of reference of type =91int&'
from expression of type =91const int'

Could anyone please help me ? Thank you so much -c

class A
{
public:
    A() {}
    typedef std::map<std::string, int> MapStuff;

    class Iterator;

    Iterator begin();
    Iterator end();
    Iterator find( const char *name );

private:

    MapStuff map;
};

class A::Iterator
{
public:
    Iterator();

    Iterator & operator ++ ();

    const std::string & name () const;
    int & value() const;

private:
    //friend class A::ConstIterator;

    A::MapStuff::iterator _i;
};

A::Iterator
A::begin()
{
    return map.begin();
}

A::Iterator::Iterator () : _i()
{
    // empty
}

A::Iterator & A::Iterator::operator ++ ()
{
    ++_i;
    return *this;
}

const std::string & A::Iterator::name () const
{
    return _i->first;
}

int & A::Iterator::value() const
{
    return _i->second;
}