Easy - Java Programming

Monday 15 February 2016

Program to take input of a number and check whether it is a Smith number

Write a program to take input of a number and check whether it is a Smith number or not.

import java.util.Scanner;

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




        if(isSmithNumber(num)){
            System.out.println(num+" is Smith Number");
        }else{
            System.out.println(num+" is not Smith Number");

        }
    }


    public static boolean isSmithNumber(int num) {

        int sumOfDigits = getSumOfDigits(num);

        int sumOfPrimeFactors = getSumOfPrimeFactors(num);

        if (sumOfDigits == sumOfPrimeFactors) {
            return true;
        } else {
            return false;

        }

    }



    public static int getSumOfPrimeFactors (int num){
    int sum=0;

    int numCopy = num;

    int divisor=2;
    while(divisor<numCopy && divisor>1){
        if(num%divisor==0){
            sum = sum + getSumOfDigits(divisor);
            num=num/divisor;
            divisor--;
        }
        divisor++;
    }

    return sum;

    }

    public static int getSumOfDigits (int num){
        int sum = 0;

        while (num > 0) {
            int digit = num % 10;
            sum = sum + digit;
            num = num / 10;
        }

        return sum;

    }

}

Java program which prints the pattern

Write a Java program which prints the following pattern on the console when the input for no. of rows (n=5).

Ans:

public class Test {
    public static void main(String[] args) {
        int rows=5;
        upper(rows);
        lower(rows-1);
    }
    static void upper(int rowCount){
        int starCount=1;
        int spaceCount=rowCount-1;
        for(int i=1;i<=rowCount;i++){
            for(int j=1;j<=spaceCount;j++){
                System.out.print(" ");
            }
            for(int j=1;j<=starCount;j++){
                System.out.print("* ");
            }
            starCount+=2;
            spaceCount--;
            System.out.println();
        }
    }
    static void lower(int rowCount){
        int starCount=rowCount*2-1;
        int spaceCount=1;
        for(int i=1;i<=rowCount;i++){
            for(int j=1;j<=spaceCount;j++){
                System.out.print(" ");
            }
            for(int j=1;j<=starCount;j++){
                System.out.print("* ");
            }
            starCount-=2;
            spaceCount++;
            System.out.println();
        }
    }

}

Java program which prints the pattern

Write a Java program which prints the following pattern on the console when the input for no. of rows (n=5).

Ans:

public class TestPattern {
   public static void main(String[] args) {
       int rows=5;
       print(rows);
   }
   static void print(int rowCount){
       int symbolCount=1;
       int spaceCount=rowCount-1;
       for(int i=1;i<=rowCount;i++){
           for(int j=1;j<=spaceCount;j++){
               System.out.print(" ");
           }
           for(int j=1;j<=symbolCount;j++){
               if(j%2==0){
                   System.out.print("* ");
               }else{
                   System.out.print(i+" ");
               }

           }
           symbolCount+=2;
           spaceCount--;
           System.out.println();
       }
   }

}

Java program which prints the pattern

Write a Java program which prints the following pattern on the console when the input for no. of rows (n=5).

A.

public class TestPattern {
    public static void main(String[] args) {
        int rows=5;
        print(rows);
    }
    static void print(int rowCount){
        for(int i=1;i<=rowCount;i++){

            boolean isEvenRow = i%2==0;
            if(isEvenRow){
                System.out.print(" ");
            }

            int columnCount = isEvenRow?(rowCount-2):rowCount;

            for(int j=1;j<=columnCount;j++){
                System.out.print("* ");
            }

            System.out.println();
        }
    }


}

Program to check the longest word and shortest word in a string

Write a java program to check the longest word and shortest word in a string.Also check their lengths.

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

        String str = "This, is";



        Test t=new Test();


        t.findLongAndShortWord(str);

    }



    public void findLongAndShortWord(String str){
        str=str+" ";
        String longestWord="";
        String shortestWord="";

        int maxLength=Integer.MIN_VALUE;
        int minLength=Integer.MAX_VALUE;

        String word="";

        for(int i=0; i<str.length(); i++){
            char ch=str.charAt(i);
            if(Character.isWhitespace(ch)){
                if(word.length()>maxLength){
                    longestWord=word;
                    maxLength =word.length();
                }

                if(word.length()<minLength){
                    shortestWord=word;
                    minLength =word.length();
                }
                word="";

            }else if(Character.isLetter(ch)){
                word+=ch;
            }

        }

        System.out.println("longest word= "+longestWord+" length= "+longestWord.length());
        System.out.println("shortest word= "+shortestWord+" length= "+shortestWord.length());

    }


}

Java program to check for Fascinating Number

Write a Program in Java to input a number and check whether it is a Fascinating Number or not..

Fascinating Numbers : Some numbers of 3 digits or more exhibit a very interesting property. The property is such that, when the number is multiplied by 2 and 3, and both these products are concatenated with the original number, all digits from 1 to 9 are present exactly once, regardless of the number of zeroes.

Let’s understand the concept of Fascinating Number through the following example:

Consider the number 192,
192 x 1 = 192
192 x 2 = 384
192 x 3 = 576

Concatenating the results : 192384576

It could be observed that ‘192384576’ consists of all digits from 1 to 9 exactly once. Hence, it could be concluded that 192 is a Fascinating Number.

Some examples of fascinating Numbers are : 192, 219, 273, 327, 1902, 1920, 2019 etc.

Programming Code:

/**

* The class FascinatingNumber inputs a number and checks if it a Fascinating Number or not

* @author : www.guideforschool.com

* @Program Type : BlueJ Program - Java

*/

import java.util.*;

class FascinatingNumber

{

    boolean isUnique(String q)

    {

        int A[] = {0,0,0,0,0,0,0,0,0,0}; //to store frequency of every digit from '0' to '9'

        int i, flag = 0;

        char ch;

        for(i=0; i<q.length(); i++)

        {

            ch = q.charAt(i);

            A[ch-48]++; 

            /*  increasing A[5] if ch='5' as '5'-48 = 53-48=5 

             *  (ASCII values of '0' to '9' are 48 to 57) */

        }

        for(i=1; i<10; i++)

        {

            //checking if every digit from '1' to '9' are present exactly once or not

            if(A[i]!=1)

            {

                flag = 1; //flag is set to 1 if frequency is not 1

                break;

            }

        }

        if(flag == 1)

            return false;

        else

            return true;

    }

    public static void main(String args[])

    {

        Scanner sc = new Scanner(System.in);

        FascinatingNumber ob = new FascinatingNumber();

        System.out.print("Enter a number : ");

        int n = sc.nextInt();

        String p = Integer.toString(n); //converting the number to String

        if(p.length()<3)

            System.out.println("Number should be of atleast 3 digits.");

        else

        {

            String s = Integer.toString(n*1) + Integer.toString(n*2) + Integer.toString(n*3);

            /*  Joining the first, second and third multiple of the number

             *  by converting them to Strings and concatenating them*/

            if(ob.isUnique(s))

                System.out.println(n+" is a Fascinating Number.");

            else

                System.out.println(n+" is not a Fascinating Number.");

        }       

    }

}

Output:

Enter a number : 273

273 is a Fascinating Number.

Enter a number : 853

853 is not a Fascinating Number.

Enter a number : 95

Number should be of atleast 3 digits.

Java Program to check for Disarium Number

Write a Program in Java to input a number and check whether it is a Disarium Number or not.

Note: A number will be called DISARIUM if sum of its digits powered with their respective position is equal to the original number.

For example 135 is a DISARIUM
(Workings 1¹+3²+5³ = 135, some other DISARIUM are 89, 175, 518 etc)

Programming Code:

/**

* The class Disarium inputs a number and checks whether

* it is a Disarium number or not

* @author : www.javaforschool.com

* @Program Type : BlueJ Program - Java

*/

import java.io.*;

class Disarium

    {

    public static void main(String[] args)throws IOException

        {

            BufferedReader br=new BufferedReader (new InputStreamReader(System.in));

            System.out.print("Enter a number : ");

            int n = Integer.parseInt(br.readLine());

            int copy = n, d = 0, sum = 0;

            String s = Integer.toString(n); //converting the number into a String

            int len = s.length(); //finding the length of the number i.e. no.of digits

            while(copy>0)

            {

                d = copy % 10; //extracting the last digit

                sum = sum + (int)Math.pow(d,len);

                len--;

                copy = copy / 10;

            }

            if(sum == n)

                System.out.println(n+" is a Disarium Number.");

            else

                System.out.println(n+" is not a Disarium Number.");

        }

    }

Output:

Enter a Number : 135
135 is a Disarium Number.
Enter a Number : 219
219 is not a Disarium Number.
Enter a Number : 89
89 is a Disarium Number.