一个简单的 C++ 程序，我到底错哪了？？

#include <iostream>
#include <string>
#include <fstream>  
using namespace std;
istream& f( istream &in )

{
    string ival;
        while (in >> ival, !in.eof())  
    {
        if(in.bad())
        throw    runtime_error("IO streamcorrupted");
        if ( in.fail() ) // bad input
        {
            cerr << " bad date, try again:";
            in.clear( );  
            continue;
        }
        cout << ival << endl;
    }
    in.clear();
    return  in;
}


int    main()
{
string filename;
cout << " enter the filename ( ctrl + z to end ):\n";
cin>>filename;
ifstream infile(filename.c_str());
if(!infile)
{
    cerr << " error: cannot open the input file:" << filename << endl;
    return -1;
}
f( infile );
system("pause");
return 0;
}


我那txt文件里面写的是hello word   然后我运行程序输入路径E:\\hello.txt  却什么也没有，文件也成功打开了（请按任意键继续。。。。）
求大神求解！！！