Java Data Types

Data Types in Java

Data Types

primitive Non primitive

Boolean Character Numeric

Integer Floating-point

charboolean byte short int long float double

Data Types in Java

byte:8-bit signed two's complement integer.Minimum value is -128 (-2^7)Maximum value is 127 (inclusive)(2^7 -1)Default value is 0Used to save space in large arrays, mainly

in place of integersExample: byte a = 100 , byte b = -50

Data Types in Java

short:16-bit signed two's complement integer. Minimum value is -32,768 (-2^15)Maximum value is 32,767 (inclusive) (2^15

-1)Used to save memoryDefault value is 0.Example: short s = 10000, short r = -20000

Data Types in Java

int:32-bit.Minimum value is -2^31Maximum value is (2^31 -1)Generally used as the default data type for

integral values unless there is a concern about memory.

The default value is 0.Example: int a = 100000, int b = -200000

Data Types in Java

long:64-bitMinimum value is (-2^63)Maximum value is (2^63 -1)This type is used when a wider range than

int is needed. Exam: light distance per yearDefault value is 0L.Example: long a = 100000L, long b = -

200000L

Data Types - long

class Light {public static void main(String args[]) {

int lightspeed;long days;long seconds;long distance;lightspeed = 186000L;days = 1000L; seconds = days * 24 * 60 * 60; distance = lightspeed * seconds; System.out.print("In " + days);System.out.print(" days light will travel about ");System.out.println(distance + " miles.");

}}

Data Types in Java

float:32-bit. Default value is 0.0f.Example: float f1 = 234.5f

Data Types in Java

double:64-bit.Default value is 0.0d.Example: double d1 = 123.4

As a decimal value multiplied by a power of 10. You can do this in Java by writing the number as a decimal value followed by an E, or an e, preceding the power of 10 that you require. For example,149,600,000 can be written as 1.496E8.

Data Types in Java

boolean:Represents one bit of information.Two possible values: true and false.Default value is false.Example: boolean one = true

Data Types in Java

char:16-bit Unicode character. Minimum value is '\u0000' (or 0).Maximum value is '\uffff' (or 65,535

inclusive).Char data type is used to store any

character.Example: char letterA ='A'

Data Types Example

public class AverageFruit {public static void main(String[] args) {

// Declare and initialize three variablesdouble numOranges = 50.0E-1; // Initial value is 5.0double numApples = 1.0E1; // Initial value is 10.0double averageFruit = 0.0;averageFruit = (numOranges + numApples)/2.0;System.out.println(“A totally fruity program”);System.out.println(“Average fruit is “ + averageFruit);

}}

OUTPUT:A totally fruity programAverage fruit is 7.5

Data Types in Java

Data Type Default Value Default size General Value

boolean false 1 bit true, false

char '\u0000' 2 byte A, b ...

byte 0 1 byte 100

short 0 2 byte (215-1) 500

int 0 4 byte 500

long 0L 8 byte 500

float 0.0f 4 byte 2.1

double 0.0d 8 byte 2.1

Data Types in JavaCategory Types

Size (bits)

Minimum Value

Maximum Value

Precision Example

Integer

byte 8 -128 127 From +127 to -128 byte b = 65;

char 16 0 216-1 All Unicode characterschar c = 'A';char c = 65;

short 16 -215 215-1 From +32,767 to -32,768 short s = 65;

int 32 -231 231-1From +2,147,483,647 to -2,147,483,648

int i = 65;

long 64 -263 263-1From +9,223,372,036,854,775,807 to -9,223,372,036,854,775,808

long l = 65L;

Floating-point

float 32 2-149 (2-2-23)·2127 From 3.402,823,5 E+38 to 1.4 E-45 float f = 65f;

double 64 2-1074 (2-2-52)·21023

From 1.797,693,134,862,315,7 E+308 to 4.9 E-324

double d = 65.55;

Otherboolean

1 -- -- false, trueboolean b = true;

Java ProgramWrite a program that display every data

type data value.

Reserved words in Java

abstract assert boolean break byte case

catch char class const* continue default

double do else enum extends false

final finally float for goto* if

implements import instanceof int interface long

native new null package private protected

public return short static strictfp super

switch synchronized this throw throws transient

true try void volatile while

special escape sequencesNotation Character represented

\n Newline (0x0a)

\r Carriage return (0x0d)

\f Formfeed (0x0c)

\b Backspace (0x08)

\s Space (0x20)

\t tab

\" Double quote

\' Single quote

\\ backslash

\ddd Octal character (ddd)

\uxxxxHexadecimal UNICODE character (xxxx)

Variable

Variable is name of reserved area allocated in memory.

int vData=50;

Types of Variable

There are three types of variables in java

local variable instance variable Class/static variable

Types of variables

class A{ 

int data=50; //instance variable  static int m=100; //static variable  void method()

{  int n=90; //local variable  }  

} //end of class 

Local variables

Declared in methods or blocks

Destroyed once it exits the method or block

Access modifiers cannot be used

Visible only within the declared method or block

There is no default value for local variables so should initialized assigned before the first use.

Local variables

public class Test{

public void pupAge(){

int age = 0; // Test without initialized

age = age + 7;

System.out.println("Puppy age is : " + age);

}

public static void main(String args[]){

Test objTest = new Test();

objTest.pupAge();

}

}

Instance variables

Instance variables are declared in a class, but outside a method, constructor or any block

When a space is allocated for an object in the heap, a slot for each instance variable value is created.

Instance variables are created when an object is created with the use of the keyword 'new' and destroyed when the object is destroyed

Access modifiers can be given for instance variables.

Instance variables have default values

Instance variables

public class Employee{ public String name; private double salary; public Employee (String empName){ name = empName; } public void setSalary(double empSal){ salary = empSal; } public void printEmp(){ System.out.println("name : " + name ); System.out.println("salary :" + salary); } public static void main(String args[]){ Employee empOne = new Employee("Ransika"); empOne.setSalary(1000); empOne.printEmp(); }

}

Class/static variables

Class variables also known as static variables are declared with the static keyword in a class, but outside a method, constructor or a block

There would only be one copy of each class variable per class, regardless of how many objects are created from it.

Static variables are created when the program starts and destroyed when the program stops.

have default values.

Class/static variables

public class Employee{ // salary variable is a private static variable private static double salary;

// DEPARTMENT is a constant public static final String DEPARTMENT = "Development ";

public static void main(String args[]){ salary = 1000; System.out.println(DEPARTMENT + "average salary:" + salary); }

}

Mathematical functionsMath.abs(-1);Math.floor(1.9);Math.ceil(1.1);java.lang.Math.sqrt(4);Math.PI;Math.pow(5, 2);Math.random()

Mathematical functions

import java.lang.Math;

public class Program { public static void main(String[] args) {

// This version uses an int.int value = Math.abs(-1);System.out.println(value);

// This version uses a double.double value2 = Math.abs(-1.23);System.out.println(value2);

int value3 = Math.abs(1);System.out.println(value3);

}}

Output1 1.23 1

Mathematical functionsimport java.lang.Math;

public class Program { public static void main(String[] args) {

// These are all reduced, even the negative number.double floor1 = Math.floor(1.9);double floor2 = Math.floor(1.1);double floor3 = Math.floor(-1.3);

System.out.println(floor1);System.out.println(floor2);System.out.println(floor3);

}}

Output1.01.0-2.0

Programs for practics Variable

Sum of two integers* / %

Java Programs