C++ ofstream/ifstream读写文件demo

#include <iostream>
#include <fstream>
using namespace std;

int main(){
//1.ofstream写入out.txt
const char * filename = "test.txt";
string end= "123456";
ofstream out("out.txt");
if(out.is_open())
{
/*
"<<":插入器，向流输出数据.
">>":析取器，向流输出数据.
*/
out<<"Hello World." << filename  << " "<< end << endl;
out.close();
}

//2.读取out.txt
ifstream in("out.txt");
char buffer[200];
if(in.is_open())
{
while(!in.eof())
{
in.getline(buffer, 100);
cout << buffer << endl;
out.close();
}
}
}