This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
SCJP Sun Certified Programmer for Java 5 Study Guide:
Character Literals A char literal is represented by a single character in single quotes.
char a = 'a'; char b = '@';
You can also type in the Unicode value of the character, using the Unicode notation of prefixing the value with \u as follows:
char letterN = '\u004E'; // The letter 'N'
Remember, characters are just 16-bit unsigned integers under the hood. That means you can assign a number literal, assuming it will fit into the unsigned 16-bit range (65535 or less). For example, the following are all legal:
char a = 0x892; // hexadecimal literal char b = 982; // int literal char c = (char)70000; // The cast is required; 70000 is // out of char range
char d = (char) -98; // Ridiculous, but legal
And the following are not legal and produce compiler errors:
char e = -29; // Possible loss of precision; needs a cast char f = 70000 // Possible loss of precision; needs a cast
You can also use an escape code if you want to represent a character that can't be typed in as a literal, including the characters for linefeed, newline, horizontal tab, backspace, and single quotes.
char c = '\"'; //A double quote char d = '\n'; //A newline
The char type (a character) contains a single, 16-bit Unicode character. Although the extended ASCII set known as ISO Latin-1 needs only 8 bits (256 different characters), a larger range is needed to represent characters found in languages other than English. Unicode characters are actually represented by unsigned 16-bit integers, which means 216 possible values, ranging from 0 to 65535 (216)-1, You'll learn in Chapter 3 that because a char is really an integer type, it can be assigned to any number type large enough to hold 65535 (which means anything larger than a short. Although both chars and shorts are 16-bit types, remember that a short uses 1 bit to represent the sign, so fewer positive numbers are acceptable in a short).
Joined: Jan 02, 2008
It is important to remember how char is related with integer (casting). For instance:
char a = 65;//implict cast by compilator: char a = (int) 65; char a = 65536;//compiler time error: to much for char
The escape characters are quite tricky:
-escape character in Java: \t The tab character ('\u0009') \n The newline (line feed) character ('\u000A') \r The carriage-return character ('\u000D') \f The form-feed character ('\u000C') \a The alert (bell) character ('\u0007') \e The escape character ('\u001B')
and literal ( almost all ):
\" \' \\
Also tricky is initialisation char. You can use:
0n The character with octal value 0n (0 <= n <= 7)
0nn The character with octal value 0nn (0 <= n <= 7)
0mnn The character with octal value 0mnn (0 <= m <= 3, 0 <= n <= 7) // char A = 0101
xhh The character with hexadecimal value 0xhh // char A = 0x41;
\uhhhh The character with hexadecimal value 0xhhhh // char A = '\u0041';