work35.cpp

#include <iostream>
using namespace std;

class CheckedPtr
{
public:
    CheckedPtr(int *b, int *e) : beg(b), end(e), curr(b) {}

    CheckedPtr &operator++();   // prefix ++
    CheckedPtr &operator--();   // prefix --
    CheckedPtr operator++(int); // postfix ++
    CheckedPtr operator--(int); // postfix --

    int *GetBeg();
    int *GetEnd();
    int *GetCurr();

private:
    int *beg;  // pointer to beginning of the array
    int *end;  // one past the end of the array
    int *curr; // current position within the array
};

// 前缀自增：先移动指针，再返回引用
CheckedPtr &CheckedPtr::operator++()
{
    if (curr < end)
        ++curr;
    return *this;
}

// 前缀自减：先移动指针，再返回引用
CheckedPtr &CheckedPtr::operator--()
{
    if (curr > beg)
        --curr;
    return *this;
}

// 后缀自增：保存当前位置，移动指针，返回保存的副本
CheckedPtr CheckedPtr::operator++(int)
{
    CheckedPtr temp = *this;
    if (curr < end)
        ++curr;
    return temp;
}

// 后缀自减：保存当前位置，移动指针，返回保存的副本
CheckedPtr CheckedPtr::operator--(int)
{
    CheckedPtr temp = *this;
    if (curr > beg)
        --curr;
    return temp;
}

int *CheckedPtr::GetBeg()
{
    return beg;
}

int *CheckedPtr::GetEnd()
{
    return end;
}

int *CheckedPtr::GetCurr()
{
    return curr;
}

int main()
{
    int n;
    cin >> n;
    int *array = new int[n];
    for (int i = 0; i < n; i++)
        cin >> array[i];

    CheckedPtr cp(array, array + n);
    for (; cp.GetCurr() < cp.GetEnd(); cp++)
        cout << *cp.GetCurr() << " ";
    cout << endl;

    for (--cp; cp.GetCurr() > cp.GetBeg(); cp--)
        cout << *cp.GetCurr() << " ";
    cout << *cp.GetCurr() << endl;

    delete[] array;
    return 0;
}