C++ 文档读取

假设有一个叫 data.txt 的文件, 它包含以下内容:

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

以下就是基于 data.txt 的数据读取操作:

#include <iostream>#include <fstream>#include <string>using namespace std;//输出空行void OutPutAnEmptyLine(){    cout<<"\n";}//读取方式: 逐词读取, 词之间用空格区分//read data from the file, Word By Word//when used in this manner, we'll get space-delimited bits of text from the file//but all of the whitespace that separated words (including newlines) was lost. void ReadDataFromFileWBW(){    ifstream fin("data.txt");      string s;      while( fin >> s )     {            cout << "Read from file: " << s << endl;      }}//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//If we were interested in preserving whitespace, //we could read the file in Line-By-Line using the I/O getline() function.void ReadDataFromFileLBLIntoCharArray(){    ifstream fin("data.txt");     const int LINE_LENGTH = 100;     char str[LINE_LENGTH];      while( fin.getline(str,LINE_LENGTH) )    {            cout << "Read from file: " << str << endl;    }}//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//If you want to avoid reading into character arrays, //you can use the C++ string getline() function to read lines into stringsvoid ReadDataFromFileLBLIntoString(){    ifstream fin("data.txt");      string s;      while( getline(fin,s) )    {            cout << "Read from file: " << s << endl;     }}//带错误检测的读取方式//Simply evaluating an I/O object in a boolean context will return false //if any errors have occurredvoid ReadDataWithErrChecking(){    string filename = "dataFUNNY.txt";      ifstream fin( filename.c_str());      if( !fin )     {           cout << "Error opening " << filename << " for input" << endl;           exit(-1);      }}int main(){    ReadDataFromFileWBW(); //逐词读入字符串     OutPutAnEmptyLine(); //输出空行    ReadDataFromFileLBLIntoCharArray(); //逐词读入字符数组    OutPutAnEmptyLine(); //输出空行    ReadDataFromFileLBLIntoString(); //逐词读入字符串    OutPutAnEmptyLine(); //输出空行    ReadDataWithErrChecking(); //带检测的读取    return 0;}

输出结果为:

Read from file: Fry:Read from file: OneRead from file: JillionRead from file: dollars.Read from file: [EveryoneRead from file: gasps.]Read from file: Auctioneer:Read from file: Sir,Read from file: that'sRead from file: notRead from file: aRead 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 inputPress any key to continue