Re: Unicode string

[Axel Freyn <axel-freyn at gmx dot de>]

Hi Eric,

On Sun, Jun 26, 2011 at 07:15:54AM -0700, eric wrote:
> Dear c/g++ advanced programers:
>  I copied and tried to test a piece simple code which is used for
> (Hardcoding a Unicode String) from the book (
> C++ Cookbook) by D. Ryan Stephens, Christopher Diggins, Jonathan
> Turkanis, and Jeff Cogswell
> at Chapter 13, Internationalization, section 1: Hardcoding a Unicode
> String
> example 13-1, it can compile and run on my g++4.5.2, but I don't quite
> satisfy its result
> 
> --------------------
> //Example 13-1 Hardcoding a Unicode string
> #include <iostream>
> #include <fstream>
> #include <string>
> 
> using namespace std;
> 
> int main() {
> 
>  // Create some strings with Unicode characters
>  wstring ws1 = L"Infinity: \u221E";
>  wstring ws2 = L"Euro: \u0128";
> 
>  wchar_t w[] = L"Infinity: \u221E";
> 
>  wofstream out("tmp\\unicode.txt");
>  out << ws2 << endl;
>  wcout << ws2 << endl;
> }
As far as I know, you should absolutely NOT use non-ascii characters in
input/output operations without explicitely specifying the
encoding/localization to be used.
In your example, I would thus propose to add after the "wofstream
out..." a line like
 out.imbue(locale("de_DE.UTF-8"));
which defines the encoding. 
The following works for me:

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main() {
 wstring ws2 = L"Euro:\x20ac";
 wofstream out("unicode.txt");
 out.imbue(locale("de_DE.UTF-8"));
 out << ws2<< endl;
}

(besides, the Euro-symbol in Unicode is \x20ac)


In addition, you SHOULD add error-checking to your code. If you add
  if(not out.good())
    cerr << "Error while writing " << endl;
AFTER the line which writes into the file, you'll get an error message ....

HTH,

Axel