Page 72 - Viva ICSE Computer Studies 8 : E-book

Variable Declaration
Declaration of a variable defi nes the data type and the name of a variable.

Syntax: <Data type><Variable name>
For example: int sum;

fl oat percentage;
Here, int and fl oat are the data types, and sum and percentage are the variable names.

We can also declare more than one variable of the same data type in a single statement,
separated by a comma.
For example: int sum, diff ;

Variable Initialisation
Initialisation means assigning a value to a variable.

Syntax: <Data type><Variable name = Initial value>;

For example: int sum = 0;

Here, sum is a variable to int data type and is assigned the value of 0.

Data Types

Data type refers to the type of data that can be used in a program. Java provides number of
data types to utilise maximum amount of memory. Some commonly used data types are as
follows.

Data Type Size Examples
int 16 bits to 32 bits 22, 45, 89, –78

fl oat, double 32 bits to 64 bits 34.78, –9.56
char 16 bits ‘a’, ‘A’, “Viva”

boolean 1 bit True, False

Operators

Operators are the special symbols used to perform calculations. Operators form an expression
when applied to variables and constants.
Example: a = b + 2

Here, a and b are the variables, ’2’ is a constant and ‘+, =’ are the operators. Let’s learn about
various operators of Java.
Arithmetic Operators

Arithmetic operators are used for various arithmetic calculations such as addition, subtraction
and so on. They include the following operators.

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