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

using namespace std;

//輸出空行
void OutPutAnEmptyLine()
{
cout << "\n";
}

//讀取方式: 逐詞讀取, 詞之間用空格區分
//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("C:\\Users\\byte\\Desktop\\huang.txt");
string s;
while (fin >> s)
{
cout << "Read from file: " << s << endl;
}
}

//讀取方式: 逐行讀取, 將行讀入字符數組, 行之間用回車換行區分
//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("C:\\Users\\byte\\Desktop\\huang.txt");
const int LINE_LENGTH = 100;
char str[LINE_LENGTH];
while (fin.getline(str, LINE_LENGTH))
{
cout << "Read from file: " << str << endl;
}
}

//讀取方式: 逐行讀取, 將行讀入字符串, 行之間用回車換行區分
//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("C:\\Users\\byte\\Desktop\\huang.txt");
string s;
while (getline(fin, s))
{
cout << "Read from file: " << s << endl;
}
}

//帶錯誤檢測的讀取方式
//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(); //逐詞讀入字符串
OutPutAnEmptyLine(); //輸出空行

ReadDataFromFileLBLIntoCharArray(); //逐詞讀入字符數組
OutPutAnEmptyLine(); //輸出空行

ReadDataFromFileLBLIntoString(); //逐詞讀入字符串
OutPutAnEmptyLine(); //輸出空行

ReadDataWithErrChecking(); //帶檢測的讀取
getchar();
return 0;
}

c++從txt中讀取數據，數據並不是一行路徑(實用)