Unicode, escape seq

[Chandra Bhatt]

public class DemoUnicode {

public static void main(String... args) {

ch\u0061r a = 'A';
\u0069nt i1 =129;
System.out.println(a);
System.out.println(i1);

}
}

Why \\u "double escape character" invalid?
I miss this concern with regex where we require "\\d" instead of "\d", we need two "\\" before d.
Please guide me!

Thanks and Regards,
cmbhatt

[Keith Lynn]

This is the grammar for a Unicode escape from the Java Language Specification.

UnicodeEscape:
\ UnicodeMarker HexDigit HexDigit HexDigit HexDigit

UnicodeMarker:
the letter you - this site won't let you put the letter by itself
UnicodeMarker u

So you don't want to start with two backslashes because that will mean the second backslash should be interpreted as just the backslash and not as part of the Unicode escape.

Also this grammar implies that you can repeated the Unicode marker.

That is, each of these seperately will compile.

ch\u0061r a = 'A';
ch\uu0061r a = 'A';
ch\uuu0061r a = 'A';
ch\uuuu0061r a = 'A';
ch\uuuuu0061r a = 'A';

,

and so on.
[ April 03, 2007: Message edited by: Keith Lynn ]

[Antonio Trapero]

And boys, dont forget,
big farms need red tractors
\b \f \n \r \t

[Chandra Bhatt]

Thanks Keith and Antonio!


Thanks and Regards,
cmbhatt