假设有一个叫 data.txt 的文件, 它包含以下内容:  

Fry: One Jillion dollars.
http://www.cnblogs.com/Images/OutliningIndicators/None.gif[Everyone gasps.]
http://www.cnblogs.com/Images/OutliningIndicators/None.gifAuctioneer: Sir, that's not a number.
http://www.cnblogs.com/Images/OutliningIndicators/None.gif数据读取， 测试 。

#include <iostream>
http://www.cnblogs.com/Images/OutliningIndicators/None.gif#include <fstream>
http://www.cnblogs.com/Images/OutliningIndicators/None.gif#include <string>
http://www.cnblogs.com/Images/OutliningIndicators/None.gif
http://www.cnblogs.com/Images/OutliningIndicators/None.gifusing namespace std;
http://www.cnblogs.com/Images/OutliningIndicators/None.gif
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//输出空行
http://www.cnblogs.com/Images/OutliningIndicators/None.gifvoid OutPutAnEmptyLine()
http://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    cout<<"\n";
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif }
http://www.cnblogs.com/Images/OutliningIndicators/None.gif
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//读取方式: 逐词读取, 词之间用空格区分
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//read data from the file, Word By Word
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//when used in this manner, we'll get space-delimited bits of text from the file
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//but all of the whitespace that separated words (including newlines) was lost. 
http://www.cnblogs.com/Images/OutliningIndicators/None.gifvoid ReadDataFromFileWBW()
http://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    ifstream fin("data.txt");  
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    string s;  
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    while( fin >> s ) 
http://www.cnblogs.com/Images/dot.gif{    
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        cout << "Read from file: " << s << endl;  
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif     }
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif }
http://www.cnblogs.com/Images/OutliningIndicators/None.gif
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//读取方式: 逐行读取, 将行读入字符数组, 行之间用回车换行区分
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//If we were interested in preserving whitespace, 
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//we could read the file in Line-By-Line using the I/O getline() function.
http://www.cnblogs.com/Images/OutliningIndicators/None.gifvoid ReadDataFromFileLBLIntoCharArray()
http://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    ifstream fin("data.txt"); 
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    const int LINE_LENGTH = 100; 
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    char str[LINE_LENGTH];  
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    while( fin.getline(str,LINE_LENGTH) )
http://www.cnblogs.com/Images/dot.gif{    
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        cout << "Read from file: " << str << endl;
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif     }
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif }
http://www.cnblogs.com/Images/OutliningIndicators/None.gif
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//读取方式: 逐行读取, 将行读入字符串, 行之间用回车换行区分
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//If you want to avoid reading into character arrays, 
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//you can use the C++ string getline() function to read lines into strings
http://www.cnblogs.com/Images/OutliningIndicators/None.gifvoid ReadDataFromFileLBLIntoString()
http://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    ifstream fin("data.txt");  
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    string s;  
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    while( getline(fin,s) )
http://www.cnblogs.com/Images/dot.gif{    
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        cout << "Read from file: " << s << endl; 
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif     }
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif }
http://www.cnblogs.com/Images/OutliningIndicators/None.gif
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//带错误检测的读取方式
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//Simply evaluating an I/O object in a boolean context will return false 
http://www.cnblogs.com/Images/OutliningIndicators/None.gif//if any errors have occurred
http://www.cnblogs.com/Images/OutliningIndicators/None.gifvoid ReadDataWithErrChecking()
http://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    string filename = "dataFUNNY.txt";  
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    ifstream fin( filename.c_str());  
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    if( !fin ) 
http://www.cnblogs.com/Images/dot.gif{   
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        cout << "Error opening " << filename << " for input" << endl;   
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        exit(-1);  
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif     }
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif }
http://www.cnblogs.com/Images/OutliningIndicators/None.gif
http://www.cnblogs.com/Images/OutliningIndicators/None.gifint main()
http://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    ReadDataFromFileWBW(); //逐词读入字符串 
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    OutPutAnEmptyLine(); //输出空行
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    ReadDataFromFileLBLIntoCharArray(); //逐词读入字符数组
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    OutPutAnEmptyLine(); //输出空行
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    ReadDataFromFileLBLIntoString(); //逐词读入字符串
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    OutPutAnEmptyLine(); //输出空行
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    ReadDataWithErrChecking(); //带检测的读取
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    return 0;
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif }
输出结果为:
Read from file: Fry:
Read from file: One
Read from file: Jillion
Read from file: dollars.
Read from file: [Everyone
Read from file: gasps.]
Read from file: Auctioneer:
Read from file: Sir,
Read from file: that's
Read from file: not
Read from file: a
Read from file: number.
Read from file: 数据读取，
Read from file: 测试
Read from file: 。

Read from file: Fry: One Jillion dollars.
Read from file: [Everyone gasps.]
Read from file: Auctioneer: Sir, that's not a number.
Read from file: 数据读取， 测试 。

Read from file: Fry: One Jillion dollars.
Read from file: [Everyone gasps.]
Read from file: Auctioneer: Sir, that's not a number.
Read from file: 数据读取， 测试 。

Error opening  dataFUNNY.txt for input
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