# include the fstream header file,and create an instance of an fstream object i.e

#include <fstream>
using namespace std;

int main () {

  fstream filestr;

  filestr.open ("test.txt", fstream::in | fstream::out | fstream::app); // open a file with mode

  // >> i/o operations here <<

  filestr.close();

  return 0;
}