質因數分解(C++) @ ！壞人必需做好事！

用Code::Block寫的，本來想用VC寫，可惜不會。

//damody
#include <iostream>
int main()
{
    unsigned long long a;
    long b = 1,d;
    char e;
    bool f;
    using namespace std;
    do
    {
        cout << "請輸入一個正整數：__________\b\b\b\b\b\b\b\b\b\b";
        f = 1;
        b = 1;
        cin >> a;
        if (a > 0 and a <= 10000000)
        {
            while (a > 1)
            {
                b++;
                if (a % b == 0)
                {
                    cout << b;
                    d = 0;
                    while (a % b == 0)
                    {
                    d++;
                    a = a / b;
                    }
                    if (d != 1)
                    cout << " ^ " << d;
                    if (a > 1)
                    cout << " * ";
                }
            }
        }
    else
    cout << "超出範圍！";
    cout << endl;
    cout << "是否繼續？(y/n)";
    cin.get();
    e = getchar();
    system("cls");
    if (e != 'y')
    f = 0;
    } while (f == 1);
    return 0;
}