Open a file for appending and append : file open mode « File Stream « C++ Tutorial

1. C++ Tutorial
2. File Stream
3. file open mode

#include <fstream>
#include <iostream>
using namespace std;
   
int main () 
{
  char buffer[256];
 
  fstream myfile;
  //open for appending and append
  myfile.open("test.txt",ios::app);
  myfile << " Hey this is another line \n";
  myfile.close();
 
  return 0;
}