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Java Programming Skills
By Mr. P. Nagaraju
Programming your passion
14/5/2020
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Content
⚫Data types
⚫Variables
⚫Operators
⚫Java example programs
⚫Assignment Questions
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Data types
⚫Data types refer to type of data that can be stored in a
variable.
⚫As Java is strongly typed language, you need to define
data type of variable to use it and you can not assign
incompatible data type otherwise the compiler will
give you an error.
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Data types
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Primitive data types
Data Type Default Value Default size
boolean false 1 bit
char ‘u0000’ 2 byte
byte 0 1 byte
short 0 2 byte
int 0 4 byte
long 0L 8 byte
float 0.0f 4 byte
double 0.0d 8 byte
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Non-primitive/Reference data types
⚫The non-primitive data types are those data types
which are provided as class by Java API or by class
that you create.
⚫The non-primitive data types include Class, String
Interface, and Array.
⚫String is an example of Reference data types provided
by java. String is an object of the class
java.lang.String.
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//Data type demo program
import java.util.*;
public class Main
{
public static void main(String[] args)
{
int myNum = 5;
float myFloatNum = 9829.33f;
char myLetter = 'D';
boolean myBool = true;
byte myByte = 100;
short myShort = 5000;
long myLong = 2500000;
double myDouble = 9829.23d;
String myText = "Hello";
String[] myBranch = {"CSE", "ECE", "EEE", “CIVIL","MECH"};
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System.out.println("int "+myNum);
System.out.println("float " +myFloatNum);
System.out.println("char "+myLetter);
System.out.println("boolean "+myBool);
System.out.println("byte "+myByte);
System.out.println("short "+myShort);
System.out.println("long "+myLong);
System.out.println("double "+myDouble);
System.out.println("String "+myText);
System.out.println("String array "+Arrays.toString(myBranch));
}// end of main function
} // end of Main Class
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9.
Variables
• These are used to store the values of
elements while the program is executed.
int x=10;
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Variables
• These are used to store the values of elements while the
program is executed.
Types of variables
• Local variable
• A Variable which is declared inside a method can be
termed as Local Variable. It is mandatory to initialize local
variable otherwise Compiler will complain about it.
• Instance variable
• A Variable which is declared at class level can be termed
as Instance variable. It is not mandatory to initialize
Instance variable.
• All instance variable will be by default initialized by JVM.
• Static variable
• A Variable which is declared as static is known
as Static variable. Static variables are class level variables.
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Variable Demo Program
public class Main
{
int a; // Instance variable
static int b=20; // static variable
public void prints()
{
int c=10; // local variable
System.out.println("Method local variable: "+c);
}
public static void main(String args[])
{ //Instance and static variable
VariableDemo demo=new VariableDemo();
System.out.println("Instance variable: "+demo.a);
System.out.println("Static variable: "+b);
demo.prints();
}
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Operators
⚫Operator in Java is a symbol which is used to
perform operations.
⚫Arithmetic Operator,
⚫Shift Operator,
⚫Relational Operator,
⚫Bitwise Operator,
⚫Logical Operator,
⚫Unary operator,
⚫Ternary Operator and
⚫Assignment Operator.
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13.
Operators in Java
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Unary Operator
class Main{
public static void main(String args[])
{
int x=10;
System.out.println(x++); // 10(11)
System.out.println(++x); //12
System.out.println(x--); //12(11)
System.out.println(--x); //10
}
}
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Shift Operators
The left shift operator << is used to shift all of the bits in
a value to the left side of a specified number of times.
The right shift operator >> is used to move left operands
value to right by the number of bits specified by the right
operand.
class Main
{
public static void main(String args[])
{
System.out.println(20<<3); //20*2^3=20*8=160
System.out.println(20>>3); //20/2^3=20/8=2
}
}
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Logical and Bitwise
Class Main{
public static void main(String args[])
{
int a=10,b=5,c=20;
System.out.println(a<b&&a<c);//false&&no checking=false
System.out.println(a<b&a<c);//false&true=false
System.out.println(a>b||a<c);//true||no checking=true
System.out.println(a>b|a<c);//true|true=true
}
}
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Ternary operator
⚫This is used as one liner replacement for if-else
statement. This is the only conditional operator which
takes three operands.
class Main{
public static void main(String args[])
{
int a=12, b=15;
int min=(a<b)?a:b;
System.out.println(min); //12
}
}
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Assignment operator
⚫It is used to assign the value on its right to the
operand on its left.
class Main{
public static void main(String args[]){
int a=10, b=20;
a+=4; //a=a+4(a=10+4)
b-=4; //b=b-4(b=20-4)
System.out.println(a); //14
System.out.println(b); //16
}}
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Assignment Questions
1. Explain Different Data types available in java with a
program?
2. Explain different operators available in java and
write a java program by using unary operators?
3. Define a variable? Write a java program which
demonstrates the types of variables?
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Google form online quiz URL
⚫https://forms.gle/CfqEcf3o91jLEPj89
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Note: Link will be activated from today 1:30pm
and works up to tomorrow 1:00pm