C++ (list) Как инициализировать переменные внутри функции без автоматического удаления? static не подходит

 template <typename value_type> 
struct list 
{ 
    class iterator 
    { 
        friend list; 
 
        iterator * previous; 
        iterator * next; 
        value_type value; 
 
        void bad_init() {previous = next = this;} 
 
        iterator() : value() {bad_init();}; 
        iterator(value_type var) : value(var) {bad_init();}; 
 
        iterator(iterator * left_iter, iterator * right_iter)  
            : previous(left_iter), next(right_iter) {}; 
 
        iterator(value_type value, iterator * left_iter, iterator * right_iter)  
            : iterator(left_iter, right_iter) {value = value;}; 
 
        public: 
            bool operator == (const iterator& another) 
            { 
                return (previous == another.previous && next == another.next && value == another.value); 
            } 
            bool operator != (const iterator& another) 
            {return !(*this == another);} 
             
            iterator& operator ++ () 
            { 
                previous = next->previous; 
                next = next->next; 
                value = next->value; 
                return *this; 
            } 
            iterator& operator -- () 
            { 
                previous = previous->previous; 
                next = previous->next; 
                value = previous->value; 
                return *this; 
            } 
             
            int& operator * () 
            { 
                return value; 
            } 
    }; 
     
    private: 
        iterator start_iter; 
        iterator end_iter; 
        unsigned int list_size; 
 
    public: 
 
    list() : list_size(2) {default_init();}; 
     
    void default_init() 
    { 
        start_iter.previous = start_iter.next = &end_iter; 
        end_iter.previous = end_iter.next = &start_iter; 
    } 
     
     
    void push_back(value_type value) 
    { 
        iterator new_iter (&end_iter, &start_iter); 
        new_iter.value = value; 
         
        start_iter.previous = end_iter.next = &new_iter; 
        end_iter = new_iter; 
         
        ++list_size; 
    } 
     
     
    iterator begin() {return start_iter;} 
    iterator end() {return end_iter;} 
    int size() {return list_size;} 
};