What are Variables, Constants, Identifiers & Data Types (in JAVA) ?

Miscellaneous 12729 05 comments

Overview:

• What are Variables?
• What are Constants?
• What are Identifiers?
• What is Data Types?
  

Today I am going to discuss Variables and Constants here w.r.t JAVA. Please note that the definition of Variables and Constants is same for all languages so, whatever I tell here is not just limited to JAVA i.e you can apply it in any language the only syntax will change.

Let me start with Variables.

 

What are Variables?

It is a name given to a memory location where value can be out. A variable can hold only a single value at a time.

Syntax:

data_type variable_name;

int a;
float b;
char c;

Value of a variable can change during execution of the program.

 

What are Constants?

Its value never changes during execution of the program.

to define a constant final keyword is used

Example:

final int A = a;

NOTE: A is a constant and it must be uppercase.

 

What are Identifiers?

It is a name given to a variable or constant or method or class.

Rules for Identifiers:-

1. It can be a combination of alphabets (a-z, A-Z) or digits (0-9) and a special character '_'.
2. Identifier name can begin with either alphabet of underscore only.
3. space should not be given in identifier.

Examples:

Identifier	Comment
a_b_c	correct
abc	correct
Abc	correct
2abc	wrong
@ab	wrong
a b c	wrong
a2b	correct
a_2b	correct

 

What is Data Types?

It specifies the type of data to be stored in a variable.

Data Types can be Predefined (or Library or Primitive) and User defined

Data Type	Comment
boolean
byte	1 byte
char	2 bytes
int	4 bytes
float	4 bytes
double	8 bytes

 

Do you have questions in your mind or just need Help?
You can ask your questions here at https://thesmartware.com/ and get it answered or helped out within hours. that's it!

We will continue to update Front; if you have any questions or suggestions, please contact us!

Follow us on Facebook, Instagram, Twitter, Pinterest, Linkedin, YouTube, and Medium.

Submit