HP assignments

Java Program to find prime number upto N number

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

[sourcecode lang=”Java”]

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);
}
}
}
}
[/sourcecode]

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

[sourcecode lang=”java”]
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);
}
}
}
}
[/sourcecode]

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

[sourcecode lang=”Java”]

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);
}
}
}
}
[/sourcecode]

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

March 13, 2016 by Java Tutorials 1

Program to find Sum of Digits in Java

Objectives :

  • Write a program to compute sum of digits of a given number.
  • Write a program to find sum of digits of a given number.
  • Write a program to calculate sum of digits of a given number.
  • Write a program to compute sum of digits of a given integer number.
  • Write a program to compute sum of digits of a number entered via Command Line.
  • Write a program to compute sum of digits of a given number. Take input from Command Line.
  • Write a program to compute sum of digits of a given number. Take input using Scanner class.

Following is the Java Program to compute Sum of Digits of a given integer number;

Method 1 : Java Program to find Sum of Digits when number is entered from command line

[sourcecode lang=”java”]

class SumOfDigits
{
public static void main(String args[])
{
int n;
int a=0;
int sum=0;

//taking integer number from command line and parsing the same
n=Integer.parseInt(args[0]);

while(n!=0)
{
a=n%10;
n=n/10;
sum=sum+a;
}
System.out.println("Sum of digits: " + sum);
}
}

[/sourcecode]

Steps to run above program via command line :

  1. Compilation : C:\JavaPrograms>javac SumOfDigits.java
  2. Interpretation : C:\JavaPrograms>java SumOfDigits 12345

Output : Sum of digits: 15

Method 2 : Java Program to find Sum of Digits if input is taken using Scanner class

[sourcecode lang=”java”]

import java.util.Scanner;

public class SumOfDigits {
public static void main(String args[]) {
Scanner in = new Scanner(System.in);
int n;
int a=0;
System.out.print("Enter a positive number: ");
n = in.nextInt();

if (n <= 0)
System.out.println("You have entered a negative number.");
else {
int sum = 0;

while (n != 0) {

a=n%10;
n=n/10;
sum=sum+a;
}
System.out.println("Sum of digits: " + sum);
}
}
}

[/sourcecode]

Steps to run above program via command line :

  1. Compilation : C:\JavaPrograms>javac SumOfDigits.java
  2. Interpretation : C:\JavaPrograms>java SumOfDigits 12345

Output :

Trial 1 : With positive number

Enter a positive number: 12345

Sum of digits: 15

Trial 2 : With negative number

Enter a positive number: -12345

You have entered a negative number.

February 23, 2016 by Java Source Code Java Tutorials 1

Simple Interest Example in Java

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 :

[sourcecode lang=”java”]
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);
}
}
[/sourcecode]

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.

[sourcecode lang=”java”]
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);
}
}
[/sourcecode]

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

[sourcecode lang=”java”]
public class MockTestProgram{

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

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.

[sourcecode lang=”java”]
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);
}
}
[/sourcecode]

 

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.

July 20, 2015 by Java Source Code Java Tutorials 0