std::cin.ignore() can be called three different ways:

1.No arguments: A single character is taken from the input buffer and discarded:
std::cin.ignore(); //discard 1 character
2.One argument: The number of characters specified are taken from the input buffer and discarded:
std::cin.ignore(33); //discard 33 characters
3.Two arguments: discard the number of characters specified, or discard characters up to and including the specified delimiter (whichever comes first):
std::cin.ignore(26, '\n'); //ignore 26 characters or to a newline, whichever comes first




舉例：
①

cin.ignore(1000, '\n')的含義是把緩沖區內從當前字符開始知道'\n'之前字符（如果有1000個的話）忽略掉，實際上你這里假設一行不會超過1000個字符，所以含義是忽略一行
②新建個文件abc.txt，然后把下面這幾句話拷貝到里面：
the, quick, brown, fox, jumps, over, the, lazy, dog

運行程序，輸入"abc.txt"。注意，abc.txt這個文件，一定要跟你這個.cpp源文件在同一個目錄里。
infile.ignore(200,','); //跳過200個字符，直到遇到','為止，所以跳過了"the,"
infile>>a; //讀入一個字符串，即"quick,"，因為默認情況下空格是讀取分隔符
infile.ignore(200,','); //跳過200個字符，直到遇到','為止，所以跳過了"brown,"
infile>>b; //讀入一個字符串，即"fox,"，注意空格是分隔符
infile.ignore(200,','); //跳過"jumps,"
infile>>c; //讀取"over,"
最后的輸出結果就是
quick,
fox,
over,

③

#include "stdafx.h"
#include
#include
#include
#include

using namespace std;
class Person{
    public:
        int id;
        string name;
        string age;
};
istream& operator>>( istream& is, Person& per ){
    is>>per.id && is.ignore() && getline(is,per.name,',') && is>>per.age;//ignore忽略掉一個字符，讀完id后跳過1個字符
    return is;
}
ostream& operator<<(ostream& os, const Person& per){
    return os << per.id << ',' << per.name << ',' << per.age;
}

int _tmain(int argc, _TCHAR* argv[])
{
    ifstream inFile("1.txt");
    if (!inFile){
        return -1;
    }

    vector personVec;

    for(Person per; inFile>>per;){
        personVec.push_back(per);
    }

    for(vector::iterator itor=personVec.begin(); itor!=personVec.end(); ++itor){
        cout << *itor << '\n';
    }
    cout << endl;


    return 0;
}

文本為：
1001,xiaoming,30
1002,Laoming,40
1003,Dming,50

若文本為
1001-xiaoming-30  則需要getline(is,per.name,',')改為getline(is,per.name,'-')

若文本為
xiaoming-30,2 則需要getline(is,per.name,'-') && is>>per.age && is.ignore() && is>>per.id;

若文本為
IF1304,2014-12-23 09:15.500
IF1305,2014-12-24 09:16.600
IF1306,2014-12-25 09:17.700
則
istream& operator>>( istream& is, Person& per ){
    //is>>per.id && is.ignore() && getline(is,per.name,'-') && is>>per.age;//ignore忽略掉一個字符，讀完id后跳過1個字符
    //getline(is,per.name,'-') && is>>per.age && is.ignore() && is>>per.id;
    getline(is,per.inst,',') && is >> per.year && is.ignore() && is >> per.month && is.ignore() && is >> per.day && is.ignore()
        && is >> per.hour && is.ignore() && is >> per.min && is.ignore() && is >> per.tick;

    return is;
}
ostream& operator<<(ostream& os, const Person& per){
    return os << per.inst << ',' << per.year << '-' << per.month << "-" << per.day << " " << per.hour << ":" << per.min << "." <<per.tick;
}
其中類為
class Person{
    public:
        string inst;
        int year;
        int month;
        int day;
        int hour;
        int min;
        int sec;
        int tick;
};

若文本為
IF1305 455 33
IF1304 4535 344
IF1345 4553 35

is >> per.inst >> per.year >> per.month;若文本中均為空格 則直接讀就行，因為----cin自動過濾tab、空格、回車?。?！