[c-prog] fixed_vector implementation problem

[Berk Acunas]

Hello,

I stuck in my fixed_vector implementation. Compiler's error message is
"C2228: left of '.begin' must have class/struct/Union. My template copy
constructor cause to this error message. I'm putting all my class' code
below and below the implementation code I put my client code. Any help
will be appreciated.

#ifndef _FIXEDVECTOR_HPP_
#define _FIXEDVECTOR_HPP_

#include <cstdio>
#include <algorithm>


template <typename T, size_t capacity>
class fixed_vector {
     T m_vd[capacity];
     int m_size;

public:
     typedef T*            iterator;
     typedef const T*    const_iterator;

     fixed_vector()
     {
         m_size = 0;

         for (int i = 0; i < capacity; ++i)
             m_vd[i] = 0;
     }

     template <typename U, size_t ucapacity>
     fixed_vector(const fixed_vector<U, ucapacity> &r)
     {
         std::copy(r.begin(), r.begin() + min(capacity, ucapacity),
this.begin());        // Error line !
     }

     template <typename U, size_t ucapacity>
     fixed_vector<T, capacity> &operator=(const fixed_vector<U,
ucapacity> &r)
     {
         std::copy(r.begin(), r.begin() + std::min(capacity, ucapacity),
this.begin());

         return *this;
     }

     iterator begin() {return m_vd;}
     iterator end() {return m_vd + capacity;}
     const iterator begin()const {return m_vd;}
     const iterator end()const {return m_vd + capacity;}

     int length() {return m_size;}

     fixed_vector<T, capacity> &push_back(T val)
     {
         if (m_size >= capacity) {
             fprintf(stderr, "Cannot enlarge fixed capacity vector!..");
             return *this;
         }

         m_vd[m_size++] = val;

         return *this;
     }


     friend std::ostream &operator<<(std::ostream &os, fixed_vector<T,
capacity> &r)
     {
         for (int i = 0; i < r.length(); ++i)
             os << r.m_vd[i] << " ";

         return os;
     }

};


#endif


/***** Client Code *****/
fixed_vector<int, 5> ifv;
fixed_vector<char, 5) cfv(ifv);