c++读写文件

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

int main()
{
    using namespace std;
    string filename;

    cout << "Enter name of new file:" << endl;
    cin >> filename;
    
    //type 1
    //ofstream fout(filename.c_str());
    
    //type 2
    ofstream fout;
    fout.open(filename.c_str()); //如果一个文件名被申明为“string”，那么就必须使用 “c_str”，然而，当你申明一个文件名为字符数组型，就没有必要使用/

    fout << "this is my test of file read and write 
" ;
    fout.close();

    //**********read*****************//
    ifstream fin(filename.c_str());
    char ch;
    // type 1
    //while (fin.get(ch))    //每次读取一个字符到ch
    //    cout << ch <<endl;
    
    //type 2
    fin >> ch;    // 读取一个字符 t
    string str;
    fin >> str; //读取 this
    cout << str << endl;

    //type 3
    //char ch2[100];
    //fin.getline(ch2,100);
    //int i = 0;
    //while(i<40)
    //{
    //    cout << "ch2[" << i << "]:" <<ch2[i]<< endl;
    //    i++;
    //}
    
    //type 4
    //string buff;
    //getline(fin,buff);
    //cout<<buff<<"

";
    //cout << "Done
";

    return 0;
}