Java IO.pdf - Nguyen Dang Binh

14.5 The char Data Type
Java I/O
The char primitive data type in Java is a two-byte unsigned integer whose values range from
to 65,535. char variables may be assigned from int literals, like this:
char exclamationPoint = 33;
In the virtual machine, chars are promoted to ints in arithmetic operations like addition and
multiplication. Therefore, operations more complicated than a simple assignment require an
explicit cast to char, like this:
char a = 97;
char b = (char) (a + 1);
In practice, chars are rarely used in arithmetic operations. Instead, they're given symbolic
meanings through mappings to particular elements of the Unicode character set. For instance,
33 is the Unicode (and ASCII) character for the exclamation point (!). 97 is the Unicode (and
ASCII) character for the small letter a. When the Unicode and printable ASCII characters
converge, as they do for values between 32 and 127, a char may be written in Java source
code as a char literal. This is the desired ASCII character between single quote marks, like
this:
char exclamationPoint = '!';
char a = 'a';
char b = 'b';
For characters outside this range, you can assign values to chars using Unicode escape
sequences, like this:
char tab = '\u0009';
char softHyphen = '\u00AD';
char sigma = '\u03C3';
char squareKeesu = '\u30B9';
14.5.1 The java.lang.Character Class
As for the other primitive data types, the core API includes a type wrapper class for char
values. This is java.lang.Character :
public final class Character implements Serializable
In Java 2 Character also implements Comparable:
public final class Character implements Serializable, Comparable // Java 2
14.5.1.1 Constructor
This class has a single constructor:
public Character(char value)
For example:
348