C / C++ / MFC

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

int main() {
  // write some characters in binary mode
  fstream file("C:\\test.txt",  ios::out | ios::binary);
  char out[]="hello";
  file.write(out, sizeof(out));
  file.close();
  
  // read the written characters
  file.open("C:\\test.txt", ios::in | ios::binary);
  char in[sizeof(out)];
  file.read(in, sizeof(in));
  cout << out << ", " << in << endl;
  file.close();
  
  return 0;
}

fstream file("c:\\test.txt",ios::in | ios::binary);
if(file.is_open())
{
   std::string s;
   file >> s;
   std::cout << s << std::endl; 
   file.close();
}
else
{
   cout<<"Error";
}