#include <iostream>
#include <vector>

int main()
{
    int length = 6;
    std::vector<char> in(length);

    in[0] = 'H';
    in[1] = 'e';
    in[2] = 'l';
    in[3] = 'l';
    in[4] = 'o';
    in[5] = '\0';

    for (int i = 0; i < length; ++i)
    {
        char a = in[i];
        std::cout << "a: " << a << std::endl;
        std::cin.putback(a);
    }

    while(std::cin)
    {
        char y;
        std::cin >> y;
        std::cout << "y: " << y << std::endl;
        if (y == '\0')
        {
            std::cout << "This is the end!" << std::endl;
        }
    }
}