#VARIABLES and TYPES# - Study24x7

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# #VARIABLES and TYPES#

Published on 10 June 2020
COMPUTER PROGRAMMING 2020
Published on 10 June 2020

## Variables and types

A variable is a data name that is used to store the data value. Constant variable cannot be changed during the execution of a program.

A variable is a symbol or name that stands for a value. It is a value that can change. A variable can take different values during the execution. It can be choose by the programmer in many ways.

Example 1:

c = a + b

This is an example of programming expression.

a, b and c are variables.

Example 2:

1. Average
2. Total
3. Count_1
4. Class_strength

In every program, variable has its own:

·Name (Identifier)

·Data Type

·Size

·Value

Variable consists of letters, digits and the underscore (_) character. It has following conditions:

1 Uppercase and lower case is significant.

For example: The variable Average is not the same as average or AVERAGE

2 They must begin with a letter.

3 It should not be a keyword.

4 White space is not allowed.

## Example of valid variable names is:

SUM1                                   ph_value                                            Mumbai

John                                     Value                                                   distance

Example of variable names

 Variable Name Valid? Remarks First_tag Valid Price\$ Not valid Dollar sign is not valid Average weight Not valid Blank space is not allowed Int_type Valid Keyword may be the part of a name

Variables can represent numeric values, characters, character strings, or memory addresses.

## Types of Variables

Local Variables                                      Instance Variables                        Static Variables

·Local variable- A variable that is declared inside the method that is called local variable.

·Instance variable- A variable that declared the inside the class but outside the method that is called instance variable.

·Static variable-A static Variable is a special type of the variable that is shared by all objects from a class. Static variable are used to keep track of global information such as number of objects from a class

Example1:-

class Simple

{

public static void main(String[] args)

{

int a=10;

int b=10;

int c=a+b;

System.out.println(c);

}

}

Example2:-

class A

{

int data=50; //instance variable

static int m=100; //static variable

void method()

{

int n=90;//local variable

}

}//end of class