Java Training in Pune

Java Program to Convert Decimal Number to Roman Number

Objectives :

  • Convert Decimal number to Roman number
  • Convert Decimal numeral to Roman numeral
  • How to convert a decimal number to roman number
  • Write a program that converts a decimal number to Roman number.
  • Write a program that converts a decimal number to Roman number. Decimal Number is accepted using Scanner class at the time of execution.
  • Write a program that converts a decimal number to Roman number. Decimal Number is accepted as command line input at the time of execution.

 

Program : 

Java program that converts a decimal number to Roman number. Decimal Number is accepted using Scanner class at the time of execution.

[sourcecode lang=”java”]

 

import java.util.Scanner;

public class DecimalToRoman {

private static String toRoman(int num) {
String[] romanCharacters = { "M", "CM", "D", "C", "XC", "L", "X", "IX", "V", "I" };
int[] romanValues = { 1000, 900, 500, 100, 90, 50, 10, 9, 5, 1 };
String result = "";

for (int i = 0; i < romanValues.length; i++) {
int numberInPlace = num / romanValues[i];
if (numberInPlace == 0) continue;
result += numberInPlace == 4 && i > 0? romanCharacters[i] + romanCharacters[i – 1]:
new String(new char[numberInPlace]).replace("\0",romanCharacters[i]);
num = num % romanValues[i];
}
return result;
}

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a number : ");
int decimal = scanner.nextInt();
System.out.println(toRoman(decimal));
}

}

[/sourcecode]

Output :

Enter a number : 1234

MCCXXXIV

Java program that converts a decimal number to Roman number. Decimal Number is accepted as command line input at the time of execution.

[sourcecode lang=”java”]

public class DecimalToRoman {

private static String toRoman(int num) {
String[] romanCharacters = { "M", "CM", "D", "C", "XC", "L", "X", "IX", "V", "I" };
int[] romanValues = { 1000, 900, 500, 100, 90, 50, 10, 9, 5, 1 };
String result = "";

for (int i = 0; i < romanValues.length; i++) {
int numberInPlace = num / romanValues[i];
if (numberInPlace == 0) continue;
result += numberInPlace == 4 && i > 0? romanCharacters[i] + romanCharacters[i – 1]:
new String(new char[numberInPlace]).replace("\0",romanCharacters[i]);
num = num % romanValues[i];
}
return result;
}

public static void main(String[] args) {
if(args.length<1 || args.length>1){
System.out.println("Wrong input");
}else{
String number = args[0];
int decimal = Integer.parseInt(number);
System.out.println(toRoman(decimal));
}
}

}

[/sourcecode]

Java Program to Convert Binary to Decimal

Objectives :

  • Binary to Decimal Conversion
  • Converting Binary to Decimal
  • Write a program to convert binary to decimal
  • Write a program to convert binary number to decimal format
  • Write a program to convert binary to decimal using Scanner class
  • Write a program to convert binary to decimal, take input using Scanner class

Java Program :

[sourcecode lang=”java”]

import java.util.Scanner;

public class BinaryToDecimal {

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print(&quot;Enter binary number: &quot;);
String binary = scanner.nextLine();
int decimal = binaryToDecimal(binary);
System.out.println(&quot;Decimal equivalent of &quot;+ binary +&quot; is &quot;+ decimal);
}

private static int binaryToDecimal(String binary) {
final int base = 2;
int decimal = 0;
for (int i = 0; i &lt; binary.length(); i++) {
if (binary.charAt(i) == ‘0’) {
decimal += 0 * Math.pow(base, binary.length() – i – 1);
} else if (binary.charAt(i) == ‘1’) {
decimal += 1 * Math.pow(base, binary.length() – i – 1);
} else {
System.out.println(&quot;Invalid Binary Number&quot;);
System.out.println(&quot;Binary Number Contains only 0’s or 1’s&quot;);
System.exit(0);
}
}
return decimal;
}
}

[/sourcecode]

Output :
Enter binary number: 1110
Decimal equivalent of 1110 is 14

Java Program to convert Decimal to Binary

Objectives :

  • Decimal to Binary Conversion
  • Converting Decimal to Binary
  • Converting Decimal Number to Binary format
  • Write a program to convert decimal to binary
  • Write a program to convert decimal number to binary format
  • Write a program to convert positive decimal number to binary format
  • Write a program to convert decimal to binary using Scanner class
  • Write a program to convert decimal to binary, take input using Scanner class

 

Java Program to convert Decimal to Binary : 

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

public void toBinary(int number){
int binary[] = new int[25];
int n = 0;
// Convert Decimal to Binary
while(number > 0){
binary[n++] = number%2;
number = number/2;
}
// Print Binary number
for(int i = n-1;i >= 0;i–){
System.out.print(binary[i]);
}
}

public static void main(String[] args){
DecimalToBinary obj = new DecimalToBinary();
obj.toBinary(14);
}
}
[/sourcecode]

Output :

1110

 

Java Program to convert Decimal to Binary using Scanner class :

[sourcecode lang=”java”]

import java.util.Scanner;

public class DecimalToBinary {

public void toBinary(int number){
int binary[] = new int[14];
int n = 0;

// Convert Decimal to Binary
while(number > 0){
binary[n++] = number%2;
number = number/2;
}

// Print Binary Number
for(int i = n-1;i >= 0;i–){
System.out.print(binary[i]);
}
}

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a number: ");
int num= scanner.nextInt();
DecimalToBinary obj = new DecimalToBinary();
obj.toBinary(num);

}
}

[/sourcecode]

Output :

Enter a number: 14

1110

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

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.