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Aatul Palandurkar

Posts Tagged ‘Java tutorial for beginners

Objectives :

  • Write a Java program to find prime number upto N number
  • Write a Java program to print prime number upto N number
  • Write a Java program to find prime number upto N number using Command Line Arguments
  • Write a Java Program to find prime number upto N number via Command Line Arguments
  • Write a Java program to find prime number upto N number using Scanner class

 

Java Program / Code :

Method 1 : Java Program to find Prime Number upto N number using Scanner class


import java.util.Scanner;
class PrimeNumber
{
public static void main(String[] args)
{
int n,p;
Scanner s=new Scanner(System.in);
System.out.println(“Enter number : ”);
n=s.nextInt();
for(int i=2;i<n;i++)
{
p=0;
for(int j=2;j<i;j++)
{
if(i%j==0)
p=1;
}
if(p==0){
System.out.println(i);
}
}
}
}

Method 2 : Java Program to find Prime Number upto N number using Scanner class and writing function to find prime number

Method isPrime() for checking if a number is prime or not

public class PrimeNumber{
 public boolean isPrime(int num) {
 if ( num < 2 ){
 return false;
 }
 for (int i = 2; i <= Math.sqrt(num); i++) {
 if ( num % i == 0 ) {
 return false;
 }
 }
 return true;
 }
}


// Mock Test Class to test above code
import java.util.Scanner;

public class Demo
{
 public static void main(String[] args) 
 {
 Scanner scanner = new Scanner(System.in);

 System.out.println("Please enter a number: ");
 int num = scanner.nextInt();
 
 if ( num < 2 ) {
 System.out.println("\n There are no Prime Numbers available");
 System.exit(0);
 }
 System.out.println("\n Prime Numbers from 1 to "+ num);
 PrimeNumber primeNum = new PrimeNumber();

 for (int i = 3; i <= num; i++) {
 if ( primeNum.isPrime(i) ) {
 System.out.print(", " + i);
 }
 }
 } 
}

Method 3 : Java Program to find Prime Number upto N number using Command line input


class PrimeNumber
{
public static void main(String[] args)
{
int n,p;
n=Integer.parseint(args[0]);
for(int i=2;i&lt;n;i++)
{
p=0;
for(int j=2;j&lt;i;j++)
{
if(i%j==0)
p=1;
}
if(p==0){
System.out.println(i);
}
}
}
}

Steps to run above program via command line :

  1. Compilation : C:\JavaPrograms>javac PrimeNumber.java
  2. Interpretation : C:\JavaPrograms>java PrimeNumber 20

Output :

2

3

5

7

11

13

17

19

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Starting a series of some Java programs as many students were asking to share the programs. Here is the first program of the series.

Objectives:

  • Write a Program that calculates and prints the simple interest using the formula : Simple Interest = PTR/100
  • How to calculate Simple Interest in Java?
  • Write a program to calculate Simple Interest in Java.
  • Write a Java program that calculates and prints the simple interest using the formula : “SimpleInterest = PTR/100” and input values P, T, R should be accepted as command line.
  • How to use Command Line Arguments in Java?
  • How to pass values from command line in Java?
  • How to take input in Java from console?

 

This particular program can be written in various ways, we will try to write the solution program in different ways here and one can try to understand the difference between them.

Method 1 :

import java.util.Scanner;

public class SimpleInterestExample {

    public static void main(String[] args) {

        int p,t,r, result;

        Scanner sc = new Scanner(System.in);

        System.out.println(&quot;Enter the Value of P : &quot;);
        p = sc.nextInt();

        System.out.println(&quot;Enter the Value of T : &quot;);
        t = sc.nextInt();

        System.out.println(&quot;Enter the Value of R : &quot;);
        r = sc.nextInt();

        result = (p*t*r)/100;
        System.out.println(&quot;Interest is : &quot; + result);
    }
}

This one is the simplest way to write the program to find simple interest in Java. Here we have simply created the object of Scanner class for taking input. Scanner class was introduced in Java 6. To use Scanner class we will have to import the class from java.util package.

Method 2:

Now we will write a Java program that calculates and prints the simple interest using the Scanner class again but with object oriented programming approach.

import java.util.Scanner;

public class SimpleInterestExample
{
		double principalAmount = 0;
        double interestRate = 0;
        double term = 0;
		double simpleInterest = 0; 

    public void calculateSimpleInterest()
	{
		Scanner input = new Scanner(System.in);

		System.out.print(&quot;Enter the Principal amount : &quot;);
		principalAmount = input.nextDouble();

		System.out.print(&quot;Enter the Rate As a decimal : &quot;);
		interestRate = input.nextDouble();

		System.out.print(&quot;Enter the amount of time in years : &quot;);
		term = input.nextDouble();

		simpleInterest = (principalAmount * interestRate * term) / 100;
	}

    public void displaySimpleInterest()
	{
		System.out.println(&quot;The Simple Interest is : &quot; + simpleInterest);
    }
}

Mock Test Program for above code so that we can test the code. keep both the classes in same package and run the Mock Test Program or MockTestProgram.java

public class MockTestProgram{

    public static void main(String[]args);
	{
		SimpleInterestExample simpleInt = new SimpleInterestExample();
		simpleInt.calculateSimpleInterest();
		simpleInt.displaySimpleInterest();
	}
}

Method 3:

Now we will write a Java program that calculates and prints the simple interest using the formula : “SimpleInterest = PTR/100” and input values P, T, R should be accepted as command line.

import java.util.Scanner;

public class SimpleInterestExample {

    public static void main(String[] args) {
		double p,t,r, result;

		p = Double.parseDouble(args[0]);
		t = Double.parseDouble(args[1]);
		r = Double.parseDouble(args[2]);

		Scanner sc = new Scanner(System.in);

		System.out.println(&quot;Enter the Value of P : &quot;);
		p = sc.nextDouble();

		System.out.println(&quot;Enter the Value of T : &quot;);
		t = sc.nextDouble();

		System.out.println(&quot;Enter the Value of R : &quot;);
		r = sc.nextDouble();

		result = (p*t*r)/100;
		System.out.println(&quot;Interest is : &quot; + result);
    }
}

 

I will be sharing more programs soon as many students were asking for programs which were carried out during Java training and were asked in assignments after Java training. By the time enjoy coding in Java and use NetBeans, it will ease your life.

Free Source Code

Free Source Code

Objective :

* How to get the MAC Address of a computer?
* How to get the MAC Address of a computer using Java?
* How to get the MAC Address of a computer via programming?

import java.net.*;

class GetMac
{
public static void main(String arg[])
{
try
{
InetAddress address = InetAddress.getLocalHost();
NetworkInterface nwi = NetworkInterface.getByInetAddress(address);
byte mac[] = nwi.getHardwareAddress();
System.out.println(mac);
}
catch(Exception e)
{
System.out.println(e);
}
}
}

Note : This code will return only the first net address; if you need other detils too, get a list.

Posted from WordPress for Android

Objective :

  • How to write a simple Java program?
  • How to write Hello in Java?
  • How to write HelloWorld in Java?
  • How to write & execute a simple Java program?
  • How to write Java program using Notepad & execute using Command Prompt?
[youtube:http://www.youtube.com/watch?v=WF0vl4x8Dm0%5D

Posted from WordPress for Android


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