ifstream两次读取最后一串文本文件

Question

我有一个简单的程序，可以读取文件中有多少单词。出于本程序的目的，单词是任何不被空格分隔的单词。我的问题是ifstream正在为我的文件读取字符串字符两次。我不明白这个？

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main() {

    ifstream infile;
    string str1;
    string filename;
    int count;

    cout << "enter a file name: ";
    cin >> filename;

    while (filename != "quit") {
        infile.open(filename.c_str());
        if (!infile) {
            cout << "Couldn't open file." << endl;
        } else {
            count = 0;
            while (infile) {
                infile >> str1;
                cout << str1 << endl;
                count++;
            }
            infile.close(); 
            cout << count << endl;
        }
        cout << "enter a filename: ";
        cin >> filename;

    }
}

以下是一个示例文件文本：

This &%file              should!!,...



have exactly 7 words.

输出：

enter a file name: file1
This
&%file
should!!,...
have
exactly
7
words.
words.
8