#include <conio.h>
#include <string.h>

void input(const unsigned n, char* const to, char* const using)
{
    int _tmp;
    unsigned i = 0;

    if (!using)
        return;

    while (i < n)
    {
        _tmp = getch();
        if (_tmp == ENTER)
        {
            to[i++] = '\0';
            break;
        }
        else if (_tmp == BACKSPACE && i > 0)
        {
            printf("\b \b");
            i--;
        }
        else if (_tmp == ESCAPE)
        {
            exit(0);
        }
        else if (_tmp == 0)
        {
            continue;
        }
        else if (strchr(using, _tmp))
        {
            to[i++] = _tmp;
            putchar(_tmp);
        }
    }
}