0123C++补习

今天在博客文集中看见一段程序，很简单的意图，但根据源程序的逻辑去无法理解，有明显的错误。
现将两段代码贴在此处，已待来日查看。

#include <iostream>
#include <stdlib.h> //used to rand()
using namespace std;

//Please guess 0 - 10 and only 9 is

int main()
{
    int rightnum = 9;
    int usernum;
    char Y_N;
    cout << "Would you roll the wheel ? (Y/N)"<<endl;
    cin >> Y_N;
    while (Y_N == 'Y' || Y_N == 'y')
    {
            usernum = rand() % 11; //rand():0~32765, use % to get 0~10
            if (usernum == 9)
            {
                        cout << "Your number is "
                             << usernum
                             << " and You are lucky !\n"; //It is a
                        break;
                        }
            else
               cout << "Your num is "
                    << usernum <<endl
                    << "Would you roll the wheel again ? (Y/N)"<<endl;
    }
    system("pause");
    return 0;
}

改正后

#include <iostream>
#include <stdlib.h> //used to rand()
using namespace std;

//Please guess 0 - 10 and only 9 is

int main()
{
    int rightnum = 9;
    int usernum;
    char Y_N;
    cout << "Would you roll the wheel ? (Y/N)"<<endl;
    abc:cin >> Y_N;
    while (Y_N == 'Y' || Y_N == 'y')
    {
            usernum = rand() % 110; //rand():0~32765, use % to get 0~10
            if (usernum == 9)
            {
                        cout << "Your number is "
                             << usernum
                             << " and You are lucky !\n"; //It is a
                        break;
                        }
            else
               cout << "Your num is "
                    << usernum <<endl;
                    //<< "Would you roll the wheel again ? (Y/N)"<<endl;
            cout<< "Would you roll the wheel again ? (Y/N)"<<endl;
            goto abc;
    }
    system("pause");
    return 0;
}