Java Reference
In-Depth Information
TABLE 2-2
Values and Memory Allocation for Integral Data Types
Data Type
Values
Storage (in bytes)
2
0 to 65535 (
¼
2
16
1)
char
2 (16 bits)
128 (
¼
2
7
) to 127 (
¼
2
7
1)
byte
1 (8 bits)
32768 (
¼
2
15
) to 32767 (
¼
2
15
1)
short
2 (16 bits)
2147483648 (
¼
2
31
) to 2147483647
(
¼
2
31
1)
int
4 (32 bits)
922337203684547758808 (
¼
2
63
)to
922337203684547758807 (
¼
2
63
1)
long
8 (64 bits)
The most commonly used integral data type is
int
. Note that the following discussion of
the
int
data type also applies to the integral types
byte
,
short
, and
long
.
int
DATA TYPE
This section describes the
int
data type, but this discussion also applies to other integral
data types. Integers in Java, as in mathematics, are numbers such as the following:
-6728, -67, 0, 78, 36782, +763
Note the following two rules from these examples:
Positive integers do not require a
+
sign in front of them.
No commas are used within an integer. Recall that in Java, commas are
used for separating items in a list. Thus,
36,782
is interpreted as two
integers:
36
and
782
.
char
DATA TYPE
As indicated in Table 2-2, the
char
data type has 65536 values, 0 to 65535. However, the
main purpose of this data type is to represent single characters—that is, letters, digits, and
special symbols. Therefore, the
char
data type can represent any key on your keyboard.
When using the
char
data type, you enclose each character represented within single
quotation marks. Examples of values belonging to the
char
data type include the following:
'A', 'a', '0', '*', '+', '$', '&', ' '
Note that a blank space is a character and is written as
' '
, with a space between the single
quotation marks.
The data type
char
allows only one symbol to be placed between the single quotation marks.
Thus, the value
'abc'
is not of type
char
. Furthermore, even though
!=
and similar special
symbols are considered to be one symbol, they are not regarded as possible values of the data
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