捕捉文本文件行中的错误，跳过和报告

我有一个文本文件，我需要阅读，每行是一个IP，一个URL，最后是一个日期，所有由空白分隔。我希望将每条信息分配给类对象"Visitor"的适当变量。我有一个数组来存储它们。我的问题是，当我试图通过文本文件，和行…我总是看到所有文本之间的空白

class Visitors{
public:
string IP;
string URL;
string dateAccessed;
};
int main(){
Visitors hits[N];
string filename, theLine;
ifstream infile;
cout << "Enter file name (with extension):" << flush;
while(true){
    string infilename;
    getline(cin, infilename);
    infile.open(infilename.c_str());
    if(infile) break;
    cout << "Invalid file. Please enter valid file name: " << flush;
}
cout << "n";
while(!infile.eof()){
    getline(infile, theLine);
    istringstream iss(theLine);
    do{
        string ip;
        string url;
        string date;
        iss >> ip;
        iss >> url;
        iss >> date;
        if(ip != "n"){
             cout << "The IP: " << ip << endl;
        }
        if(url != "n"){
             cout << "The URL: " << url << endl;
        }
        if(date != "n"){
            cout << "The DA: " << date << endl;
        }

    }while(iss);
}
return 0;
}

我尝试使用if语句来抓取所有只是"新行"的字符串并忽略它们，但这不起作用，所以我不完全确定如何忽略它们。我还想添加检查，看看是否有任何信息是错误的(日期不是2/2/4字符长，缺少www。)

下面是一些示例输出，以更好地展示我的问题…

Enter file name (with extension):hits.txt
The IP: 192.168.1.101
The URL: www.cs.stonybrook.edu
The DA: 01/01/2013
The IP:
The URL:
The DA:
The IP: 192.168.1.101
The URL: www.cs.stonybrook.edu
The DA: 01/01/2013
The IP:
The URL:
The DA:
The IP: 123.112.15.151
The URL: www.cs.stonybrook.edu
The DA: 01/01/2013

编辑:好吧，所以我已经弄清楚如何通过每一行，打破它，并添加相应的字符串，它属于在对象数组中的类变量。现在的问题是，我想检查每一行的每个字符串的错误(例如:日期是不可能的，或者IP中的一个数字是256等等)。在发现这个错误后，我想跳到下一行，做同样的检查，如果一切正常，它将在数组中的适当位置初始化类变量。下面是我的代码，以了解我想做什么…

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
#define N 50
using namespace std;
class Visitors{
public:
string IP;
string URL;
string dateAccessed;
};
int main(){
Visitors hits[N];
string infilename, filename, ip, url, date;
ifstream infile;
int i = 0;
cout << "Enter file name (with extension):" << flush;
while(true){
    infilename = "";
    getline(cin, infilename);
    infile.open(infilename.c_str());
    if(infile) break;
    cout << "Invalid file. Please enter valid file name: " << flush;
}
cout << "Loading " << infilename << "..." << endl;;
cout << "n";
while(infile.good()){
    string line;
    getline(infile, line);
    stringstream ss(line);
    if(ss >> ip >> url >> date){
        cout << "The IP: " << ip << endl;
        hits[i].IP = ip;
        cout << "The URL: " << url << endl;
        hits[i].URL = url;
        cout << "The DA: " << date << endl;
        hits[i].dateAccessed = date;
        i++;
    }
    else{
        cerr << "error" << std::endl;
    }
    /*
    if(ip.length() > 15 || ip.length() < 7){
        cout << "Found a record with an invalid IP format (not XXX.XXX.XXX.XXX)...ignoring entry";
    }
    //if(any of the numbers in the IP address are great then 255)
        //INVALID IP...IGNORE ENTRY
    else{
        cout << "The IP: " << ip << endl;
        hits[i].IP = ip;
    }
    //if(url doesnt start with www. or doesnt end with .xxx)
        //INVALID URL...IGNORE ENTRY
    else{
        cout << "The URL: " << url << endl;
        hits[i].URL = url;
    }
    //if(date.length != 10)
        //INVALID DATE FORMAT...IGNORE ENTRY
    //if(first 2 numbers in date arent between 01 and 12
         //OR if second 2 numbers arent between 01 and 31 depending on month OR etc.)
         //INVALID....IGNORE ENTRY
    else{
        cout << "The DA: " << date << endl;
        hits[i].dateAccessed = date;
    }
    i++;*/
}
return 0;
}

它显然没有组织或放在一起，它实际上是如何在程序中，但它是我想要完成的总体思路。我最大的问题是如何在不干扰的情况下跳过文件中的一行，比如我在数组中的位置，或者如果所有行都有错误，它会捕获每一个。