Fundamental Data Types & Assigning variables in java

Assigning The Variables 

Definition : A variable must be given a value after it has been declared but before it is used in an expression. This can be achieve in two ways. They are :

  1. By using an assignment statement.

  2. By using a read statement.

➤ Assignment Statement :-  A simple method of giving values to a variable is through the assignment statement as follows. Already we  discussed about on the data type declaration in last post then we have assigning the variable to that data types.

 Syntax:- variable name= value;

  

Here variable name represents the name of the type that specify location of the value in the memory. Value is used to  store the value of the variable name. Some of the example are given below.

Example:- ID NO =100;
                      percentage = 80.1;
                      PI = 3.14;
                      grade = 'A';
we are also string assignment expressions as shown below  a=b=c=0; .

➤ It is also possible to assign a value to a variable at the time of its declaration. This is taken the form:

Syntax:-  Data type variable name = value;

Example:-  int Id NO = 100;
                       float percentage = 80.1f;
                       double pi = 3.14;
                       char grade ='A';

The process of giving initial values to variables is known as the initialization values. The ones that are not initialization are automatically set to zero.

Fundamental Data-Types 

In Computer science programming, a data type or type clarify the data which tells the computer or interpreters that how the programmer intends to use the data. A most of the programming languages support various type of data that will use for like example: Real, Integer or Boolean . 

In previous post we have already discuss  about on the data type and their types in the real industry. The  below following  are  the  Fundamental  data types  and  their  categories also  memory sizes in Java . 

Definition 

Data types specify the size and type of values that can be stored in primary memory of a computer. The below diagram shows about that on data type and their types in java.

Consider the below  table specify the data types in java under various categories.

Category Type       Data Type          Memory Size

                                             byte                                1 byte 

                                                                         

                                             short                              2 byte

➤ Integer Category         int                                   4 byte

  

                                             long                                8 byte

                                             float                                4 byte

➤ Float

                                             double                           8 byte

➤ Character                      char                               2 byte

➤ Boolean                         boolean                         1 byte

➽Data types are classified into two types. They are :

1. Primitive data type 

    i . Numeric  

        a. Integer  b.  Floating point

    ii. Non-Numeric

        a. Character   b. Boolean

2. Non-primitive  data type

    i. Classes

    ii. Arrays

    iii. Interfaces

➤  Integer :- Integer types can hold the whole numbers. Java supports fours types of  integers, They are given below.

 Type                      Size

Byte                                           one byte

Short                                         two byte

int                                              four byte

long                                           eight byte

➤ Floating point :- Floating point data type can hold the number with fractional parts. Java supports two types of data types.

Type                       Size

float                                       four byte

double                                   eight byte

➤ Character type :-  Character data type is used to store the character constants in main memory. The memory size is two bytes.

➤ Boolean type :- Boolean type is used when we want to rest a particular conditions during the execution of the program. Either it must be true or false.

➤ Classes :- A class is a collection of methods and variables (or) A self contained block of statement's is called a class.

➤ Array :- An array is a group of related data items that share a common name.

➤ Interface :- It is a named called collection of methods definitions.