DATA TYPES & VARIABLES
Data Type specifies the format, range of values and memory requirement of data that a data element can hold.
Hierarchy of Data Types in Java:
- Primitive
- Integral
- Numeric
- Integer
- Byte
- Short
- Int
- long
- Decimal
- Float
- double
- Character
- Integer
-
- Boolean
- Non-Primitive
- Class
- Array
Range of Signed Values for any Data Type based on its Memory Requirement:
Minimum Value: -2(n-1)
Maximum Value: +2(n-1) – 1
Range of Unsigned Values for any Data Type based on its Memory Requirement:
Minimum Value: 0
Maximum Value: +2(n-1)
Java Primitive Data types
|
Data type |
Description |
Example |
Groups |
|
Byte |
Byte-lenth integer |
10, 24 |
Integer |
|
Short |
Short Integer |
500, 786 |
|
|
Int |
Integer |
89, 945, 37865 |
|
|
Long |
Long Integer |
89L, -945L |
|
|
Float |
Single-precision floating point |
89.5f, -32.5f |
Floating point Numbers |
|
Double |
Double-precision floating point |
89.5, -35.5, 87.6E5 |
|
|
Char |
Single Character |
‘c’, ‘9’, ‘t’ |
Characters |
|
Boolean |
Boolean value (0 or 1) |
True or False |
Boolean |
In most of the languages, the format and size of primitive data types depend on the platform on which a code is running. But in Java programming language, size and format of its primitive data types is specified.
Integer & Floating-point numbers fall under Numeric datatypes. Java has six numeric datatypes that differ in size and precision of the numbers they can hold. The Size means how many bits are needed to represent the data type. The Range of a data type expresses the precision of numbers.
Four categories of Integer data types
|
Type |
Values |
Default |
Size |
Range |
|
Byte |
Signed int |
0 |
8 bits (1 byte) |
-128 to 127 |
|
Short |
Signed int |
0 |
16 bits(2 bytes) |
-32768 to 32767 |
|
Int |
Signed int |
0 |
32 bits (4 bytes) |
-2147483648 to 2147483647 |
|
Long |
Signed int |
0 |
64 bits(8 bytes) |
-9223372036854775808 to 9223372036854775807 |
Float Data types
|
Float |
IEEE 754 floating point |
0.0 |
32 bits |
+/- 1.4e-45 to +/- 3.4028235e+38, +/- infinity, +/-0, NAN |
|
double |
IEEE 754 floating point |
0.0 |
64 bits |
+/- 4.9e-324 to +/- 1.7976931348623157e+308, +/- infinity, +/-0, NAN |
Character Data type
|
Type |
Values |
Default |
Size |
Range |
|
Char |
Unicode Character |
\u0000 |
16 bits |
\u0000 to \uFFFF |
Boolean data type
|
Type |
Values |
Default |
Size |
Range |
|
Boolean |
True, False |
False |
1 bit used in 32 bit integer |
NA |