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I have been trying to find out the Why am I getting a ' ' when I print a char variable which was initialized with the default value of '\u0000'?

Also I know that float and double has a default value of "0.0f" and "0.0d", but here when I print their default values the suffix "f" and "d" are not printed. So why are these suffixes not printed with the values?

Here's the code: 

class Check{
    char c;
    float f;
    double d;

    public static void main(String a[]) {
        Check obj = new Check();
        System.out.println("Default value of char : " + obj.c);
        System.out.println("Default value of float : " + obj.f);
        System.out.println("Default value of double: " + obj.d);
    }
}

In the code for default value of char is printed as ' '. For float it is "0.0" and for double is "0.0". In short my question is: Why am I getting a ' ' instead of '\u0000' or null (or something like this) for char? Why the suffix present in the default values of float and double are not printed? (like "0.0f" and "0.0d")

Note: There are other questions like: Primitives/Objects Declaration, default initialization values and what's the default value of char?, but unlike my question these questions discuss only about their default values not about printing them.

Community
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    Those suffixes have no meaning outside of java code, so when you print the values, suffixes don't appear. The same goes for "\u" prefix, when you print a char value, you are actually printing the corresponding character (by the way, the default character value '\u0000' is not null, and is a non-printable character, giving different outputs depending on your system : empty, square..) . – Arnaud Dec 12 '15 at 11:47
  • @Berger thanks for the reason behind suffix, so it means these will never be printed on execution? and if('\u0000') it is non-printable then why there is ' ' why not no ' ' at all ? –  Dec 12 '15 at 11:55
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    Yes, suffixes will never get printed to the console, or a file, or a Socket, They are internal stuff of the java code, nothing more.Non-printable characters are represented in different forms, but if you attempt to print one, the system is supposed to output something, the 'something' will depend on the platform, but it isn't supposed to ignore your print EVEN THOUGH it has no way to display it correctly.. – Arnaud Dec 12 '15 at 12:01
  • So,it means on different platforms i'll be getting different output for default value of char('\u0000') just because it is non-printable character ? –  Dec 12 '15 at 12:09
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    Exactly, each system will decide on how it will display a non-displayable character.If it ever makes sense :) – Arnaud Dec 12 '15 at 12:16
  • @Berger For clarification n correct ans , you could have posted this as whole as answer . –  Dec 12 '15 at 12:21
  • @PrayagSharma Thank you for creating your own question and you now got your answer for this. :) – Tom Dec 12 '15 at 19:17

2 Answers2

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Those suffixes have no meaning outside of java code, so they will never get printed to the console, or a file, or a Socket.

The same goes for "\u" prefix (java does internally use Unicode), when you print a char value, you are actually printing the corresponding character .

The default character value '\u0000' is not null, and is a non-printable character, giving different outputs depending on your system : empty, a square...

If you attempt to print one, the system is supposed to output something, the 'something' will depend on the platform, but it isn't supposed to ignore your print EVEN THOUGH it has no way to display it correctly.

Arnaud
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Things that come to my mind right now:

  1. In your code you miss the final "}", for class Check.

  2. Have you try printing just

    System.out.println(obj.c); // Without the String

    Adding the String may read the null ass a '' and the d and f as part of the format, so it just print 0.0.

  3. When you print ascii code for some values java compiler reads it as a the intended valu, with this I mean that probably when you print the char it prints a "\u0000", but when the compiler reads it he makes it a '', same with the format of float and double values. In context is like printing a \n, you just can't because of interpreted as a semicolon.

user207421
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Alejandro Cortes
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  • (1) isn't an answer. (2) will make no difference. (3) is hopelessly confused, and 'because of interpreted as a semicolon' is meaningless. Answer is full of 'may' and 'probably', i.e. guesswork. – user207421 Dec 12 '15 at 20:34