c++文件操作

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

void ex1_xtra2()
{
    //输入一个文件名称
    string file_name;
    cout << "Please enter a file to be opened: (try input.txt or text.txt) ";
    cin >> file_name;

    //判断是否为空
    if ( ! cin || file_name.empty() )
    {
        cerr << "oops! unable to read file namen"; return;
    }

    //建立一个读取的ifile，由于读取 input.txt中的内容
　　
    ifstream ifile( file_name.c_str() );

    if ( ! ifile )
    {
        cerr << "oops! unable to open input file: "
             << file_name << endl;
        return;
    }
    else
    {
        cerr << "!! ok: opened " << file_name << " for inputn";
    }

    //新建一个input.txt.sort文件，用于保存排好序的文字
    //类型是输出ofile
    file_name += ".sort";
    ofstream ofile( file_name.c_str() );

    if ( ! ofile )
    {
        cerr << "oops! unable to open output file: "
             << file_name << endl;
        return;
    }
    else
    {
        cerr << "!! ok: opened " << file_name << " for outputn";
    }


    string word;
    vector< string > text;
    //读取内容到word至文件末尾
    while ( ifile >> word )
    {
        //插入到容器text中
        text.push_back( word );
    }

    if ( text.empty() )
    {
        cerr << "bummer! input file is empty: bailing outn";
        return;
    }
    else
    {
        cerr << "!! ok: read " << text.size() << " strings from inputn";
    }
    //排序操作
    sort( text.begin(),text.end() );

    int cnt = 0;
    for ( vector<string>::iterator iter = text.begin();
            iter != text.end(); ++iter )
    {
        //排列格式
        cnt += iter->size() + 1;
        if ( cnt > 40 )
        {
            ofile << ‘n‘; 
            cnt = 0;
        }
        //输出到ofile中，即input.txt.sort文件中
        ofile << *iter << ‘ ‘;
    }

    cout << "ok: wrote sorted strings into " << file_name << endl;
}

int main(void)
{
    ex1_xtra2();
    return 0;
}

Alice Emma has long flowing red hair.  
Her Daddy says when the wind blows 
through her hair,it looks almost alive,like a fiery bird in flight.  A beautiful 
fiery bird,he tells her,magical but untamed.  
``Daddy,shush,there is no such thing,‘‘ she 
tells him,at the same time wanting him to 
tell her more.  Shyly,she asks,``I mean,Daddy,is there?‘‘

A Alice Daddy Daddy,Emma Her Shyly,``Daddy,``I a alive,almost asks,at beautiful 
bird bird,blows but fiery fiery flight. 
flowing hair,hair. has he her her her,him 
him,in is is it like long looks magical 
mean,more. no red same says she she shush,such tell tells tells the the there there?‘‘ 
thing,‘‘ through time to untamed. wanting when 
wind