regex_iterator使用自定义迭代器的问题

我想对文本进行正则表达式搜索，我想从文本中跳过某些字符。这里问的原始问题:正则表达式库，维护状态，输入字符逐个字符，并返回true每当找到匹配为此，我做了一个自定义迭代器，并试图将这些迭代器传递给regex_iterator。但我得到以下错误:

regex(2775): error C2512: 'fixed_array::iterator' : no appropriate default constructor available
          with
          [
              T=char
          ]
regex(2773) : while compiling class template member function 'std::tr1::regex_iterator::regex_iterator(void)'
          with
          [
              _BidIt=fixed_array::iterator
          ]
iterator.cpp(168) : see reference to class template instantiation 'std::tr1::regex_iterator' being compiled
          with
          [
              _BidIt=fixed_array::iterator
          ]
regex(2775): error C2512: 'fixed_array::iterator' : no appropriate default constructor available
          with
          [
              T=char
          ]

下面是我的代码:

    template 
    class fixed_array
    {
        public:
        typedef int size_type;
        class iterator
        {
            public:
            typedef iterator self_type;
            typedef T value_type;
            typedef T& reference;
            typedef T* pointer;
            typedef std::bidirectional_iterator_tag iterator_category;
            typedef int difference_type;
            iterator(pointer ptr) : ptr_(ptr) { }
            self_type operator++() /*skip character 'a'*/
            {
                self_type i = *this;
                ptr_++;
                if(*ptr_ == 'a')
                ptr_++;
                return i;
            }
            self_type operator++(int junk)
            {
                ptr_++;
                if(*ptr_ == 'a')
                ptr_++;
                return *this;
            }
            reference operator*()
            {
                return *ptr_;
            }
            pointer operator->()
            {
                return ptr_;
            }
            bool operator==(const self_type& rhs)
            {
                return ptr_ == rhs.ptr_;
            }
            bool operator!=(const self_type& rhs)
            {
                return ptr_ != rhs.ptr_;
            }
            private:
            pointer ptr_;
        };
        class const_iterator
        {
            public:
            typedef const_iterator self_type;
            typedef T value_type;
            typedef T& reference;
            typedef T* pointer;
            typedef int difference_type;
            typedef std::bidirectional_iterator_tag iterator_category;
            const_iterator(pointer ptr) : ptr_(ptr) { }
            self_type operator++() { self_type i = *this; ptr_++; return i; }
            self_type operator++(int junk) { ptr_++; return *this; }
            const reference operator*() { return *ptr_; }
            const pointer operator->() { return ptr_; }
            bool operator==(const self_type& rhs) { return ptr_ == rhs.ptr_; }
            bool operator!=(const self_type& rhs) { return ptr_ != rhs.ptr_; }
            private:
            pointer ptr_;
        };

        fixed_array(size_type size) : size_(size) {
            data_ = new T[size_];
        }
        size_type size() const { return size_; }
        T& operator[](size_type index)
        {
            assert(index < size_);
            return data_[index];
        }
        const T& operator[](size_type index) const
        {
            assert(index < size_);
            return data_[index];
        }
        iterator begin()
        {
            return iterator(data_);
        }
        iterator end()
        {
            return iterator(data_ + size_);
        }
        const_iterator begin() const
        {
            return const_iterator(data_);
        }
        const_iterator end() const
        {
            return const_iterator(data_ + size_);
        }
        private:
        T* data_;
        size_type size_;
    };
    using namespace std;
    int main()
    {
        fixed_array<char> point3d(50);
        //initialize the array with some string.
        regex e ("a.*ea");
        fixed_array<char>::iterator beg = point3d.begin();
        fixed_array<char>::iterator end = point3d.end();
        regex_iterator<fixed_array<char>::iterator> rit ( beg, end, e );
        regex_iterator<fixed_array<char>::iterator> rend;
        while (rit!=rend) {
            cout << rit->str() << std::endl;
            ++rit;
        }
        return 0;
    }