Data types and Literals




                          1
Objectives

On completion of this period, you would be able to
 know

•   Data types in Java
•   Literals in Java




                                                     2
Recap


In the previous class we have discussed
   •   White spaces, separators, literals and keywords
   •   Comments in Java




                                                         3
Data types in Java
• Data types in Java are classified into
   • Primitive types
   • Non-primitive types
• Primitive types are also known as simple data
  types
• A primitive type is predefined by the language
• Primitive types are further classified into
   • Numeric types
   • Non-numeric types



                                               4
Data types in Java
• Non-primitive types are also known as reference
  types
• Non-primitive types are
  • Classes
  • Interfaces
  • Arrays




                                                5
The classification of data types in Java
                             Data types in Java



             Primitive                         Non-primitive

 Numeric         Non-numeric
                                            classe            Arrays
                                            s
 integer
                      char                        Interface

Floating point             Boolea
                           n
                         Fig. 6.1 Data types in Java
                                                                  6
Data types

•   Primitive Java data types can be grouped into
    •   integers
    •   floating point numbers
    •   characters
    •   boolean




                                                    7
Integer types

•   Java defines four integer types: byte, short, int and
    long
•   All these are signed, positive and negative values
•   Java does not support unsigned types
•   byte is 8 bit width , short is 16 bit width int is 32
    bit width and long is 64 bit width



                                                            8
byte type

•   The smallest type is byte
•   Range from -128 to +128
•   Byte variables are declared by use of keyword
    ‘byte ‘
     eg.
         byte x, y;




                                                    9
short type

•  short is a signed 16 bit type.
• Its range is from -32,768 to +32,767

• It is probably the least used data type in Java

• Keyword used is ‘short’

eg.
  short x;




                                                    10
int type

•     The most commonly used integer data type is int
•     It has a range of -2,147,483,648 to 2,147,483,647
•     Keyword used is ‘int’
eg.
    int x;




                                                     11
long type
•   long is a signed 64 bit type
•   Useful where an int type is not large enough to hold
    the desired value
•   The range of large is quite large
•   This makes it useful when large, whole numbers are
    needed
•   Keyword used is ‘long’
eg. :
    long seconds;
                                                      12
floating point types

•   floating point numbers are also known as real
    numbers
•   Are used when fractional components are required
•   float and double are two kinds of floating point
    types
•   Keywords used are ‘float’ and ‘double’


                                                       13
Float type

•   float specify a single precision value that uses 32
    bits of storage
•   float type is useful when you require fractional
    component, but does not require a large degree of
    precision
eg.
    float area;

                                                          14
double type

•   double uses 64 bits of storage
•   When you need to maintain accuracy over many
    iterative calculations or manipulating large valued
    numbers double is the best choice
eg. :
    double area;


                                                      15
character type

•   In Java the data type used to store character is char
•   char in Java is different from char in C and C++
•   Java used Unicode to represent characters
•   Unicode was selected because it would help in
    internationalization of Java as a programming
    language
•   Java character is 16 bit type. The range of the
    characters is 0 to 65,536


                                                       16
boolean type

•   boolean data type is used to represent logical
    values that can be either true or false
•   All relational, conditional and logical operators
    return boolean values
•   It used only one bit of storage
•   Keyword used is ‘boolean’
•   eg;.
    •   boolean flag;



                                                        17
The simple data types in Java
•   In summary Java defines eight simple types of
    data. They are
    •   byte
    •   short
    •   int
    •   long
    •   char
    •   float
    •   double
    •   boolean

                                                    18
Summary
•   In this class we have discussed
    •   Data types in Java
    •   Literals in Java




                                      19
Quiz
1.Which of the following data type can store only
   two values
a)   int
b)   float
c)   boolean
d)   All of the above


                                                    20
Quiz

2.String Literal Enclosed with

a)   ‘‘
b)   ““
c)   **
d)   All the Above



                                 21
Frequently Asked Questions

1.   List the different data types available in Java

2.   Explain the various data types available in Java

3.   List the Literal in Java

4.   Explain the Literals in Java



                                                       22

Data types

  • 1.
    Data types andLiterals 1
  • 2.
    Objectives On completion ofthis period, you would be able to know • Data types in Java • Literals in Java 2
  • 3.
    Recap In the previousclass we have discussed • White spaces, separators, literals and keywords • Comments in Java 3
  • 4.
    Data types inJava • Data types in Java are classified into • Primitive types • Non-primitive types • Primitive types are also known as simple data types • A primitive type is predefined by the language • Primitive types are further classified into • Numeric types • Non-numeric types 4
  • 5.
    Data types inJava • Non-primitive types are also known as reference types • Non-primitive types are • Classes • Interfaces • Arrays 5
  • 6.
    The classification ofdata types in Java Data types in Java Primitive Non-primitive Numeric Non-numeric classe Arrays s integer char Interface Floating point Boolea n Fig. 6.1 Data types in Java 6
  • 7.
    Data types • Primitive Java data types can be grouped into • integers • floating point numbers • characters • boolean 7
  • 8.
    Integer types • Java defines four integer types: byte, short, int and long • All these are signed, positive and negative values • Java does not support unsigned types • byte is 8 bit width , short is 16 bit width int is 32 bit width and long is 64 bit width 8
  • 9.
    byte type • The smallest type is byte • Range from -128 to +128 • Byte variables are declared by use of keyword ‘byte ‘ eg. byte x, y; 9
  • 10.
    short type • short is a signed 16 bit type. • Its range is from -32,768 to +32,767 • It is probably the least used data type in Java • Keyword used is ‘short’ eg. short x; 10
  • 11.
    int type • The most commonly used integer data type is int • It has a range of -2,147,483,648 to 2,147,483,647 • Keyword used is ‘int’ eg. int x; 11
  • 12.
    long type • long is a signed 64 bit type • Useful where an int type is not large enough to hold the desired value • The range of large is quite large • This makes it useful when large, whole numbers are needed • Keyword used is ‘long’ eg. : long seconds; 12
  • 13.
    floating point types • floating point numbers are also known as real numbers • Are used when fractional components are required • float and double are two kinds of floating point types • Keywords used are ‘float’ and ‘double’ 13
  • 14.
    Float type • float specify a single precision value that uses 32 bits of storage • float type is useful when you require fractional component, but does not require a large degree of precision eg. float area; 14
  • 15.
    double type • double uses 64 bits of storage • When you need to maintain accuracy over many iterative calculations or manipulating large valued numbers double is the best choice eg. : double area; 15
  • 16.
    character type • In Java the data type used to store character is char • char in Java is different from char in C and C++ • Java used Unicode to represent characters • Unicode was selected because it would help in internationalization of Java as a programming language • Java character is 16 bit type. The range of the characters is 0 to 65,536 16
  • 17.
    boolean type • boolean data type is used to represent logical values that can be either true or false • All relational, conditional and logical operators return boolean values • It used only one bit of storage • Keyword used is ‘boolean’ • eg;. • boolean flag; 17
  • 18.
    The simple datatypes in Java • In summary Java defines eight simple types of data. They are • byte • short • int • long • char • float • double • boolean 18
  • 19.
    Summary • In this class we have discussed • Data types in Java • Literals in Java 19
  • 20.
    Quiz 1.Which of thefollowing data type can store only two values a) int b) float c) boolean d) All of the above 20
  • 21.
    Quiz 2.String Literal Enclosedwith a) ‘‘ b) ““ c) ** d) All the Above 21
  • 22.
    Frequently Asked Questions 1. List the different data types available in Java 2. Explain the various data types available in Java 3. List the Literal in Java 4. Explain the Literals in Java 22