从aa.txt里输入string到程序中（前提是txt里有string），输出他们

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
 using namespace std;//从aa.txt里输入string到程序中（前提是txt里有string），输出他们
void process(string s)
{
    cout<<s;
}
int main()
{
    vector<string> files;
    string FileName,s;

    cout<<"Enter filenames:(Ctrl+Z to end)" <<endl;
    while(cin>>FileName)
        files.push_back(FileName);
    ifstream input;
    vector<string>::const_iterator it=files.begin();

    while(it!=files.end()){
        input.open(it->c_str());
        if(!input){
            cerr <<"error:can not open file:" <<*it <<endl;
            ++it;}
        else{
            while(input>>s)
                process(s);
            input.close();
            input.clear();
            ++it;
        }
    }
    return 0;
}