6-28 for循环

//?Q求出1000以内的完数
//有一分数序列 1/2，2/3，3/5，5/8，8/13，13/21
{
    double firsta = 1;
    double firstb = 2;

    double firstc = 0;

    double seconda = 0;
    double secondb = 0;

    double secondc = secondb / seconda;

    double sum = 0;

    for (int i = 0; i < 20; i++)
    {
        seconda = firstb;
        secondb = firsta + firstb;
        firstc = firstb / firsta;
        cout << firstc << endl;
        firstb = secondb;
        firsta = seconda;
        sum += firstc;
    }
    cout << sum;

    system("pause");
}