: A variable stores data on the basis of datatypes in java

Posted by Gyan Guide on May 18th, 2017

Introduction :

Datatypes defines the type of data that a variable can store .

Based on the data type of a variable, the operating system allocates memory and decides what can be stored in the reserved memory. Therefore, by assigning different data types to variables, we can store integers, decimals, or characters in these variables.

About Datatypes :

       Datatype is a spacial keyword used to allocate sufficient memory space for the data, in other words Data type is used for representing the data in main memory (RAM) of the computer.

 There are two types of data types are  available in Java −

  1)Primitive Data Types

  2)Reference/Object Data Types/Non primitive java course in bangalore  data types

Primitive Data Types :

Primitive datatypes are the datatypes  those are already defined in java.

These are eight in numbers  . Primitive datatypes are predefined by the language and named by a keyword.

These are – byte , short , int , long , float , double , Character , boolean

byte

-         Byte data type is an 8-bit signed two's complement integer

-         Minimum value is -128( i.e.- 2^7)

-         Maximum value is 127 (i.e. 2^7-1)

-         Default value is 0

-         It  is used to save space in large java/j2ee classes bangalore  arrays, mainly in place of integers, since a byte is four times smaller than an integer.

-         Example: byte  x = 101 , byte y = -54

short

-         Short data type is a 16-bit signed two's complement integer

-         Minimum value is -32,768 (-2^15)

-         Maximum value is 32,767 (2^15 -1)

-         Short data type can also be used to save memory as byte data type. A short is 2 times smaller than an integer

-         Default value is 0.

-         Example: short  x = 10000, short  y = -20000

int :

-         Int data type is a 32-bit signed two's complement  Advanced java training in bangalore  integer.

-         Minimum value is - 2,147,483,648 (-2^31)

-         Maximum value is 2,147,483,647 (2^31 -1)

-         Integer is generally used as the default data type for integral values unless there is a concern about memory.

-         The default value is 0

-         Example: int  x = 100000, int  y = -200000

long :

-         Long data type is a 64-bit signed two's complement integer

-         Minimum value is -9,223,372,036,854,775,808(-2^63)

-         Maximum value is 9,223,372,036,854,775,807 (2^63 -1)

-         This type is used when a wider range than int is needed

-         Default value is 0L

-         Example: long  x = 100000L, long  y= -200000L java/j2ee classes bangalore

Float :

-         Float data type is a single-precision 32-bit IEEE 754 floating point

-         Float is mainly used to save memory in large arrays of floating point numbers

-         Default value is 0.0f

-         Float data type is never used for precise values such as currency

-         Example: float f1 = 234.5f

Double :

-         double data type is a double-precision 64-bit IEEE 754 floating point

-         This data type is generally used as the default data type for decimal values, generally the default choice

-         Double data type should best core java training in bangalore  never be used for precise values such as currency

-         Default value is 0.0d

-Example: double  x = 121.9

Boolean :

-         boolean data type represents one bit of information

-         There are only two possible values: true and false

-         This data type is used for simple flags that track true/false conditions

-         Default value is false

-         Example: boolean one = true

Char :

-         char data type is a single 16-bit Unicode character

-         Minimum value is '\u0000' (or 0)

-         Maximum value is '\uffff' (or 65,535 inclusive)

-         Char data type is used to store any character

-         Example: char letterA = 'A'

Reference Datatypes/Nonprimitive datatype :

               These are the data types  java course in bangalore  which are derived from the                existing datatypes

-         Reference variables are created using defined constructors of the classes. They are used to access objects. These variables are declared to be of a specific type that cannot be changed. For example, Employee, Student , etc.

-         Class objects and various type of array variables come under reference datatype.

-         Default value of any reference variable is null.

-         A reference variable can be used to refer any object of the declared type or any compatible type.

-         Example: Employee emp = new Employee(“abc”);

Some Important points :

-         All numeric data types java training center bangalore  are signed(+/-).

-         The size of data types remain the same on all platforms (standardized)

-         char data type in Java is 2 bytes because it uses UNICODE character set. By virtue of it , Java supports internationalization. UNICODE is a character set which covers all known scripts and language in the world.

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