Iterator

#include <iostream>
#include <windows.h>
#include <ctime>
#include <algorithm>
#include <string>

using namespace std;
class Iterator;
class Vector
{
    int *arr;
    int size;
public:
    friend Iterator;
    Iterator begin();
    Iterator end();
    Vector() { arr = NULL; size = 0; }
    Vector(int s = 0)
    {
        if (s > 0)
        {
            size = s;
            arr = new int[s];
            for (int i = 0; i < s; i++)
                arr[i] = 0;
        }
    }
    ~Vector()
    {
        if (arr)
            delete[]arr;
    }
    Vector(const Vector & B)
    {
        if (B.size > 0)
        {
            size = B.size;
            arr = new int[size];
            for (int i = 0; i < size; i++)
                arr[i] = B.arr[i];
        }
        else
        {
            size = 0;
            arr = 0;
        }
    }
    void PrintV() { for (int i = 0; i < size; i++)printf_s("%d ", arr[i]); printf_s("\n"); }
    void ScanV()
    {
        for (int i = 0; i < size; i++)
            cin >> arr[i];
    }
    int Get_size()
    {
        return size;
    }
    int Get_el(int i)
    {
        return arr[i];
    }
    Vector operator *(const Vector &B)
    {
        Vector C(size);
        if (size == B.size)
        {
            for (int i = 0; i < size; i++)
                C.arr[i] = arr[i] * B.arr[i];
            return C;
        }
        else
            printf_s("\nРазмерности векторов не совпадают\n");
        return *this;

    }
    Vector operator *(int d)
    {
        for (int i = 0; i < size; i++)
            arr[i] = arr[i] * d;
        return *this;
    }
    Vector operator +(const Vector&B)
    {
        Vector C(size);
        if (size == B.size)
        {
            for (int i = 0; i < size; i++)
                C.arr[i] = arr[i] + B.arr[i];
            return C;
        }
        else
            printf_s("\nРазмерности векторов не совпадают\n");
        return *this;
    }
    Vector operator +(int d)
    {
        for (int i = 0; i < size; i++)
            arr[i] = arr[i] + d;
        return *this;
    }
    Vector operator -(const Vector&B)
    {
        Vector C(size);
        if (size == B.size)
        {
            for (int i = 0; i < size; i++)
                C.arr[i] = arr[i] - B.arr[i];
            return C;
        }
        else
            printf_s("\nРазмерности векторов не совпадают\n");
        return *this;
    }
    Vector operator -(int d)
    {
        for (int i = 0; i < size; i++)
            arr[i] = arr[i] - d;
        return *this;
    }
    bool operator >(const Vector &B)
    {
        int s1 = 0, s2 = 0;
        for (int i = 0; i < size; i++)
        {
            s1 = s1 + arr[i] * arr[i];
            s2 = s2 + B.arr[i] * B.arr[i];
        }
        if (s1 > s2)
            return true;
        return false;

    }
    bool operator <(const Vector &B)
    {
        int s1 = 0, s2 = 0;
        for (int i = 0; i < size; i++)
        {
            s1 = s1 + arr[i] * arr[i];
            s2 = s2 + B.arr[i] * B.arr[i];
        }
        if (s1 <s2)
            return true;
        return false;
    }

    Vector operator =(const Vector &B)
    {
        if (arr)
            delete[] arr;
        size = B.size;
        arr = new int[size];
        for (int i = 0; i < size; i++)
            arr[i] = B.arr[i];
        return *this;
    }
    bool operator ==(const Vector &B)
    {
        for (int i = 0; i < size; i++)
            if (arr[i] != B.arr[i])
                return false;
        return true;
    }
    bool operator !=(const Vector &B)
    {
        for (int i = 0; i < size; i++)
            if (arr[i] != B.arr[i])
                return true;
        return false;
    }

};

class Iterator
{
public:
    int *m;
public:
    friend Vector;
    Iterator(int *a = 0) :m(a) {}
    bool operator ==(const Iterator & it)
    {
        return (m == it.m);
    }
    bool operator !=(const Iterator & it)
    {
        return (m != it.m);
    }

    Iterator operator ++();
    Iterator operator --();
};

Iterator Vector::begin()
{
    Iterator it(arr);
    return it;
}
Iterator Vector::end()
{
    Iterator it(arr);
    for (size_t u = 0u; u < size; ++u)
    {
        ++it;
    }
    return it;
}
Iterator Iterator::operator ++()
{
    return ++m;
}

Iterator Iterator::operator --()
{
    return --m;
}
int main()
{
    setlocale(LC_ALL, "Rus");
    Vector A(4);
    A.ScanV();
    Vector B(A);
    A.PrintV();
    Iterator it(A.begin());
    //Iterator iter = A.begin();
    cout << A.begin().m << " " << A.end().m << endl;
    for(Iterator iter = A.begin(); iter != A.end(); ++iter)
    {
        cout << *iter.m << endl;
    }
    system("pause");

    return 0;
}