#include < iostream >
#include < fstream >
#include <
string
>

using namespace std;


// 输出空行

void OutPutAnEmptyLine()

{
cout<<" ";
}

// 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 strings

void 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 occurred

void 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;
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