如何在C ++中正确读取输入文件？

Question

我对C ++比较陌生，所以请原谅使用命名空间std。我试图从文件中读取数值，并确定其主要因素。尽管没有失败，它将忽略输入，显示无限循环的“0＆＃39; 0＆＃39; 0和＆＃39; 2是素数＆＃39;。下面是我的代码和文本文件。

代码：

#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
using namespace std; 
int main()
{
    int div = 0, num = 0, count = 0;
    string inputFile;
    ifstream fin;

    cout << "Enter input file name: ";
    getline(cin, inputFile);
    fin.open(inputFile.c_str());

    if (fin.fail())
    {
        cout << "Bad file.\n";
        cin.ignore();
        getchar();
        exit(0);
    }

    fin >> num;
    cout << left << setw(12) << "Number" << setw(15) << "Prime Factors\n" 
    << "---------------------------\n"
    << setw(12) << num << endl;

    while (!fin.eof())
    {
        div = 2;
        count++;
        cout << setw(15) << num;
        if (num < 0)
            cout << "Can't do negative numbers\n"
        else
        {
            cout << div;
            while (div <= num / 2)
            {
                if (num % div == 0)
                {
                    num = num / div;
                    cout << div;
                }
                else
                    div++;
            }
        }
        if (div >= num / 2)
            cout << "is a prime number\n";
        fin.ignore(10, '\n');
        fin >> num;
        cout << setw(12) << num << endl;
    }
    if (count == 0)
        cout << "No data was processed, data file is empty.\n";
    cin.ignore(10, '\n');
    getchar();
    return (0);
}

Input.txt（以EoF的单数空行结尾）：

348     
23