ELEMENTARY PROGRAMMING - Introduction to Java Programming: Comprehensive Version - page 41

tells the compiler to allocate appropriate memory space for the variable based on its data type.
The syntax for declaring a variable is
datatype variableName;
Here are some examples of variable declarations:
int count; // Declare count to be an integer variable
double radius; // Declare radius to be a double variable
double interestRate; // Declare interestRate to be a double variable

declare variable

These examples use the data types int and double . Later you will be introduced to addi-
tional data types, such as byte , short , long , float , char , and boolean .
If variables are of the same type, they can be declared together, as follows:
datatype variable1, variable2, ..., variablen;
The variables are separated by commas. For example,
int i, j, k; // Declare i, j, and k as int variables
Variables often have initial values. You can declare a variable and initialize it in one step.
Consider, for instance, the following code:

initialize variables

int count = 1 ;

This is equivalent to the next two statements:

int count;
count = 1 ;

You can also use a shorthand form to declare and initialize variables of the same type
together. For example,

int i = 1 , j = 2 ;

Tip
A variable must be declared before it can be assigned a value. A variable declared in a
method must be assigned a value before it can be used.
Whenever possible, declare a variable and assign its initial value in one step. This will
make the program easy to read and avoid programming errors.

Every variable has a scope. The scope of a variable is the part of the program where the
variable can be referenced. The rules that define the scope of a variable will be introduced
gradually later in the topic. For now, all you need to know is that a variable must be declared
and initialized before it can be used.

2.5

✓ ✓

Identify and fix the errors in the following code:

Check

Point

1 public class Test {
2 public static void main (String[] args) {
3 int i = k + 2 ;
4 System.out.println(i);
5 }
6 }

2.6 Assignment Statements and Assignment
Expressions
An assignment statement designates a value for a variable. An assignment statement
can be used as an expression in Java.

Key
Point