int main(int argc, const char * argv[])
{
    for(int i = 0;;++i)
    {
        cout << i << endl;
        if (_kbhit())
        {
            int c = _getch();
            if (c == 0x1B) break;
        }
    }
}

for(int i = 0;;++i)
{
    cout << i << endl;
    if(_kbhit())
    {
        while(_kbhit()) _getch();
    }
    else
    {
        _getch();
    }
}

while(_kbhit()) _getch();