如何读取txt文件中的内容

怎么读取txt文件中的内容？
包括读取其中的内容和写入，

请贴完整代码及原理注释

[解决办法]

C/C++ code

#include <iostream>#include <fstream>using namespace std;int main(int argc, char** argv){    char aline[1024];    // 想文本文件写入    ofstream fos("e:/file.txt");    if(!fos)    {        cout << "Can not open file..." << endl;    }    fos << "This is line 1 to be written into file.txt" << endl;    fos << "This is line 2 to be written into file.txt" << endl;    fos << "This is line 3 to be written into file.txt" << endl;    fos.close();    // 读文本文件内容    ifstream fis("e:/file.txt");    if(!fis)    {        cout << "Can not open file..." << endl;    }    while(fis)    {        memset(aline, 0, 100);        fis.getline(aline, 100);        if(aline[0] == 0) break;        cout << aline << endl;    }    return 0;}