C++ create a file in Unicode instead of Ansi

Question

Why C + +, create a Unicode file if you try to write a structure like this in the file? Part of the code:

struct stEjemplo
{
    char cadena1[9];
    char cadena2[9];
};

Write what I write in cadena1 and cadena2 shows me something like this in the file:

㈱㐳㘵㠷㠀㘷㐵㈳o

Example:

fstream file("File.dat");
if(!file.is_open())
{
    file.open("File.dat", ios::in | ios::out | ios::trunc);
}
stEjemplo somest = {0};
strcpy(somest.origen, "SomeText");
strcpy(somest.destino, "SomeText");
file.clear();
file.seekg(0,ios::beg); //ios::end if existing information
file.write(reinterpret_cast< char*>(&somest), sizeof(stEjemplo));
file.close();

Results this:

潓敭敔瑸匀浯呥硥t

Note the "t" in final (is the "t" in final of the second "SomeText")

But if my structure was:

struct stEjemplo
{
    int number; //then I assign 1324
    char cadena1[9];
    char cadena2[9];
};

Results: , SomeText SomeText or

struct stEjemplo
{
    bool x; //then I assign true o false
    char cadena1[9];
    char cadena2[9];
};

would result something like: SomeText SomeText

EDIT:

If the 00 (NULL character) in hex editor is set in odd position (starting at 0, for example: 1, 3, 5, 7, 9, etc etc) I have the problem, but if the 00 is set in a pair position and is not preceded by another 00, the problem is solved.

Answer 1

You are opening File.dat in your text editor as UTF-16LE when it quite clearly isn't, open it in plain ASCII or UTF-8 (or even use a hex editor) and you should see the strings.

潓敭敔瑸匀浯呥硥t corresponds to the UTF-16LE sequence

53 6F 6D 65 54 65 78 74 00 53 6F 6D 65 54 65 78 74 00

guess what this is when read as plain ASCII / UTF-8?

Answer 2

This is a bad way of handling things. It may even be undefined behavior (due to padding of the struct members).

It would be better to write serialization code for your struct:

#include <cstring>
#include <fstream>
#include <iostream>

struct stEjemplo
{
    char cadena1[9];
    char cadena2[9];
};

std::ostream& operator<<(std::ostream& os, const stEjemplo& e)
{
  return os << e.cadena1 << ' ' << e.cadena2;
}

int main()
{
  stEjemplo somest = {};
  std::strcpy(somest.cadena1, "SomeText");
  std::strcpy(somest.cadena2, "SomeText");
  std::ofstream file("File.dat", std::ios::trunc);
  if(!file)
  {
    std::cout << "Failed opening file.\n";
  }
  file << somest;
  file.close();

  // no error checking, assuming all will go well
  std::ifstream test("File.dat");
  std::string contents;
  std::getline(test, contents);
  std::cout << contents;
}

Live demo here.

Also:

• consider using std::string instead of char[] and strcpy.
• consider using std::ios::binary when writing raw data like encoded strings.

Answer 3

Known Notepad bug. Not your fault.