2

The question is quite simple; if I have the following string:

string str = "\0test";

How can I display the character "\0" in a label in WinForms, where it seems to cut off all characters after the "\0", or more generally in a Console output, where it seems to insert space instead of the "\0"?

Console.WriteLine(str);
label.Text = str;
Stephen Kennedy
  • 20,585
  • 22
  • 95
  • 108
some_user
  • 179
  • 11

4 Answers4

1

See C# ASCII reference.

The \0 character terminate a sting and should not be printable, since it is used to terminate a String.

Let's replace the \0 with ° as termination Symbol. Example Strings:

  1. abcd°
  2. ab°cd°
  3. °abcd°
  4. °°

Note: The system terminates the strings automatically, so all end in an °. So, if you would print any of those, you get:

  1. abcd
  2. ab
  3. (space is mandatory, represents empty)
  4. (space is mandatory, represents empty)

Since the system terminates at the first appearance of the termination symbol.

Thriem
  • 11
  • 1
  • 2
  • `The \0 character terminate a string` Are you sure about that? [This answer](https://stackoverflow.com/a/2292867) seems to contradict your statement. – some_user Jul 20 '19 at 20:51
  • 1
    The ASCII symbol (with index 0) is used as Termination symbol. Thus it has no (default) representation. It's up to the implementation if they make use of it or not - I will clarify that C# does not use it - but neither does it print it in any meaningful way. – Thriem Jul 20 '19 at 20:58
1

To display all the string you should prefix it with @:

string str = @"\0test";

for more about verbatim string check this question What's the @ in front of a string in C#?

Hamza
  • 440
  • 7
  • 20
  • 1
    In case it's not obvious, the string from the question is not the same as the string in this answer: `"\0test" != @"\0test"`. In particular, the question refers to the character `"\0"`, which indeed is one character. `@"\0"` is two characters. – Tom Blodget Jul 21 '19 at 12:22
  • Yes, but he only needed to display that string and i answered how – Hamza Jul 22 '19 at 22:52
  • That's fine. I'm just clarifying for future readers that it's the right answer to the wrong question. The question asker should rewrite the question if this is the answer. – Tom Blodget Jul 22 '19 at 23:08
1

You are asking to display "unprintable" characters. Fonts generally don't have glyphs for these and, where appropriate, renderers interpret TAB, LF and CR for positioning rather than glyphs.

One way is to replace them with Control Picture characters. 

String str = "\0test";
var controlCharacters = new Regex(@"([\u0000-\u001F])");
String displayStr = controlCharacters.Replace(str, m => ((Char)(m.Groups[1].Value[0] + '\u2400')).ToString());

// ␀test

You might still have the problem of your users' fonts not supporting these characters. (Some browsers don't either so it might be hard to see what I'm talking about.)

Tom Blodget
  • 20,260
  • 3
  • 39
  • 72
0

Double backslash:

string str = "\\0test";

String str now contains \0test

TheProgrammer
  • 58
  • 10