C++中对文本的读写

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


using namespace std;
int main()
{
string s1="test",s2="mskdkndk",s3="bdbdhbdhb";
string  out=s1+"\t"+s2+"\t"+s3;
fstream fout;
fout.open("yyy",ios::out);
fout<<out<<endl;
string in;
fstream  fin;
fin.open("yyy",ios::in);


fin>>in;
cout<<in<<endl;

}