Aatul Palandurkar

Posts Tagged ‘HP Internship Assignments’

Java Program to find prime number upto N number

Posted on: March 13, 2016

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;
{
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);

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);

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

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

```
{
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 :

2. Interpretation : C:\JavaPrograms>java PrimeNumber 20

Output :

2

3

5

7

11

13

17

19

Program to find Sum of Digits in Java

Posted on: February 23, 2016

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

```
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);
}
}

```

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

```
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);
}
}
}

```

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.