Aatul Palandurkar

Posts Tagged ‘Free Java Source Code

Objectives:

  • Write a Java program to to generate random numbers and print the same
  • Write a program to generate random numbers
  • Write a program to generate random numbers in Java

Java Program:


import java.util.Scanner;
import java.util.Random;

class GenerateRandomNumber
{
public static void main(String[] args)
{
int maxRange;

//create objects
Scanner SC = new Scanner(System.in);
Random rand = new Random();

System.out.print("Please enter maximum range: ");
maxRange=SC.nextInt();

for(int i=1; i<=10; i++)
{
System.out.println(rand.nextInt(maxRange));
}
}
}

Output:

Please enter maximum range: 500
467
61
100
449
68
316
445
224
54
498

Objectives:

  • Write a Java program to find duplicate characters in the string and print the duplicate characters
  • Write a program to find duplicate characters in String

Java Program:

public class DuplicateCharacters {
    public static void main(String args[]) {

        String str = "NITIN";
        int count = 0;

        char input[] = str.toCharArray();
        System.out.println("Duplicate Characters are:");

        for (int i = 0; i &amp;lt; str.length(); i++) {
            for (int j = i + 1; j &amp;lt; str.length(); j++) {
                if (input[i] == input [j]) {
                    System.out.println(input[j]);
                    count++;
                    break;
                }
           }
        }
    }
}

Output:

Duplicate Characters are: N I

Objectives:

  • How to use switch case in Java?
  • How to use switch case with string in Java?
  • How to pass string literals in switch case in Java?

 

Source Code:


public class SwitchWithStringExample

{
public static void main(String[] args)
{
String str = "two";
switch(str)
{
case "one":
System.out.println("one");
break;
case "two":
System.out.println("two");
break;
case "three":
System.out.println("three");
break;
default:
System.out.println("no match");
} // switch close
} // main close
} // class close

 

Steps to run above Java code:

Consider that we have saved code at C drive (c:\>) and the file is saved as SwitchWithStringExample.java

  1. Compilation : c:\> javac SwitchWithStringExample.java
  2. Interpretation : c:\> java SwitchWithStringExample

 

Output:

two

 

We conduct Java Training and Workshop for Corporates and College Students, if interested, please write to us on kloudsancyber@gmail.com

 

Aatul Palandurkar
International Trainer, and Author, NetBeans Dream Team Member

https://www.facebook.com/aatulpalandurkar
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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.


&nbsp;

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));
}

}

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.


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));
}
}

}

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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