自定义istream结束迭代器

#include <iostream>
#include <iterator>

class CustomIstreamIterator : public std::iterator<std::input_iterator_tag, int>
{
private:
    std::istream& input;
    int value;
    bool isEnd;

public:
    CustomIstreamIterator(std::istream& in) : input(in), isEnd(false)
    {
        ++(*this);
    }

    CustomIstreamIterator() : input(std::cin), isEnd(false)
    {
        ++(*this);
    }

    CustomIstreamIterator& operator++()
    {
        if (!(input >> value))
        {
            isEnd = true;
        }
        return *this;
    }

    CustomIstreamIterator operator++(int)
    {
        CustomIstreamIterator tmp(*this);
        ++(*this);
        return tmp;
    }

    int operator*() const
    {
        return value;
    }

    bool operator==(const CustomIstreamIterator& other) const
    {
        return isEnd == other.isEnd;
    }

    bool operator!=(const CustomIstreamIterator& other) const
    {
        return !(*this == other);
    }

    bool isEndOfInput() const
    {
        return isEnd;
    }
};

int main()
{
    std::cout << "Enter some numbers (enter a non-integer to end): ";

    CustomIstreamIterator begin(std::cin);
    CustomIstreamIterator end;

    for (CustomIstreamIterator it = begin; it != end; ++it)
    {
        std::cout << *it << " ";
    }

    std::cout << std::endl;

    return 0;
}