C++文件输入输出

#include <iostream>  //有些系统里面可以省略此头文件
#include <fstream>
#include <string>

int main()
{
    using namespace std;

    string filename;

    cout << "please enter name for new file" << endl;
    cin >> filename;

    ofstream  fout( filename.c_str());

    fout << "For your eyes only! 
";
    cout << "Enter your secret number: ";
    string secret;
    cin >> secret;
    fout <<"Your secret number is " <<secret << endl;
    fout.close();

    ifstream fin(filename.c_str());
    cout << "Here are the contents of " << filename << ":
";
    char ch;
    while (fin.get(ch))
    {
        cout << ch;
    }

    cout << "Done!
";

    fin.close();
    return 0;
}