Session 5 / Operator and Control Statements

Introduction (5 minutes)

Operators in Java (20 minutes)

Control Statements (20 minutes)

Assessment (5 minutes)

Operators

Various operators that are used in Java are enlisted in following Pics.

Arithmetic Operators

The arithmetic operators are used to perform basic arithmetic operations. The operands used for these operators must be of numeric type. The Boolean type operands can not be used with arithmetic operators.

Java Program

//Program for demonstrating arithmetic operators

class ArithOperDemo

{

public static void main(String[] args)

{

System.out.println("\n Performing arithmetic operations ");

int a 10,b=20,c;

System.out.println("a = "+a);

System.out.println("b= "+b);

c=a+b;

System.out.println("\n Addition of two numbers is "+c);

c=a-b;

System.out.println("\n Subtraction of two numbers is "+c);

c=a*b;

System.out.println("\n Multiplication of two numbers is "+c);

c=a/b;

System.out.println("\n Division of two numbers is "+c);

}

}

Output

Performing arithmetic operations

a= 10

b= 20

Addition of two numbers is 30

Subtraction of two numbers is -10

Multiplication of two numbers is 200

Division of two numbers is 0

Relational Operators

Output

The relational operators typically used to denote some condition. These operators establish the relation among the operators. The <><>= are the relational operators. The result of these operators is a Boolean value.

Java Program

//Program for demonstrating relational operators

import java.io.*;

import java.lang.*;

import java.util.*;

public class RelOper

{

public static void main(String args[])

{

int a,b,c;

a=10;

b=20;

if(a>b)

{

System.out.println("a is largest");

}

else

{

System.out.println("b is largest");

}

}

}

Logical Operators

The logical operators are used to combine two operators. These two operands are Boolean operators.

Java Program

//Program for demonstrating logical operators

import java.io.*;

import java.lang.*;

public class LogicalOper

{

public static void main(String args[])throws IOException

{

boolean oper1,oper2;

oper1=true;

oper2=false;

boolean ans1,ans2;

ans1=oper1&oper2;

ans2=oper1|oper2;

System.out.println("The oper1 is: "+oper1);

System.out.println("The oper2 is: "+oper2);

System.out.println("The oper1&oper2 is: "+ans1);

System.out.println("The oper1 | oper2 is: "+ans2);

}

}

Output

The oper1 is: true

The oper2 is: false

The oper1&oper2 is: false

The oper1 oper2 is: true

Special Operators

• There are two special operators used in Java-instanceof and dot operators.

• For determining whether the object belongs to particular class or not- an instanceof operator is used. For example-

• Ganga instanceof River if the object Ganga is an object of class River then it returns true otherwise false.

• The dot operator is used to access the instance variable and methods of class objects.

For example -

Customer.name //for accessing the name of the customer

Customer.ID //for accessing the ID of the customer

Conditional Operator

The conditional operator is "?" The syntax of conditional operator is

Condition?expression1:expression2

Where expression1 denotes the true condition and expression2 denotes false condition.

For example:

a>b?true:false

This means that if a is greater than b then the expression will return the value true otherwise it will return false.