Tag: java special program

In his tutorial, we will learn how to write a java program to check bouncy number. Before we code, let us understand what is a bouncy number.

Bouncy Number

A number is said to be a bouncy number if the digits of that number are in random order that is not sorted. Example: 121575, 521634, etc.

In other words, a number that is neither an increasing number nor a decreasing number is called a bouncy number.

• Increasing number: The number whose current digit is greater than or equal to the previous digit is called an increasing number. Example: 12345, 45678, etc.
• Decreasing number: The number whose current digit is less than the previous digit is called an decreasing number. Example: 54321, 98765, etc.

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Bouncy Number Program in Java

import java.util.*;

public class Main
{
  public static void main(String args[])
  {
    int num;
    Scanner scan = new Scanner(System.in);

    System.out.print("Enter the number: ");
    num = scan.nextInt();

    //calling function and checking condition
    if (isIncreasing(num) || isDecreasing(num) || num < 101)
      System.out.println(num + " is NOT a Bouncy number");
    else
      System.out.println(num + " is a Bouncy number");
  }

  //user-defined function to check for incresing number
  public static boolean isIncreasing(int num)
  {
    String str = Integer.toString(num);
    char digit;
    boolean flag = true;

    for (int i = 0; i < str.length() - 1; i++)
    {
      digit = str.charAt(i);
      if (digit > str.charAt(i + 1))
      {
        flag = false;
        break;
      }
    }

    return flag;
  }

  //user-defined function to check for decreasing number
  public static boolean isDecreasing(int num)
  {
    String str = Integer.toString(num);
    char digit;
    boolean flag = true;
    for (int i = 0; i < str.length() - 1; i++)
    {
      digit = str.charAt(i);
      if (digit < str.charAt(i + 1))
      {
        flag = false;
        break;
      }
    }

    return flag;
  }
}

Output:

//Run 1
Enter the number: 12345
12345 is NOT a Bouncy number

//Run2
Enter the number: 23561
23561 is a Bouncy number

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In this tutorial, we will learn about Krishnamurthy numbers and write a Krishnamurthy Number program in Java. We will write two programs for Krishnamurthy number in java.

Krishnamurthy Number

A number is said to be a Krishnamurthy Number if the sum of the factorial of all digits of a number is equal to the original number itself. Krishnamurthy Number is also known as Strong number and is frequently asked questions in interviews.

Example:

Input: 145
Output: Krishnamurthy Number
= 1! + 4! + 5!
= 1 + 24 + 120
= 145
= Original Number

---

Java Program to check Krishnamurthy Number

import java.util.Scanner;

public class KrishnamurthyProgram
{
   // boolean function to check Krishnamurthy Number
   public static boolean isKrishnamurthy(int number)
   {
      int sum = 0, lastDigit = 0;
      int temp = number;

      // iterating through all the digits
      while (temp != 0)
      {
         lastDigit = temp % 10;
         sum += factFunc(lastDigit); //calling factFunc func for every digit
         temp /= 10;
      }

      // returns true if number and sum are equal
      if (sum == number)
         return true;
      return false;
   }

   //user defined function to calculate the factorial
   public static long factFunc(int n)
   {
      long fact = 1;
      for (int i = 1; i <= n; i++)
         fact *= i;

      return fact;
   }

   // main function
   public static void main(String[] args)
   {
      int num = 0;
      boolean checkResult = false;


      Scanner scan = new Scanner(System.in);

      // user input
      System.out.print("Enter an integer: ");
      num = scan.nextInt();

      // calling function by passing the entered number
      checkResult = isKrishnamurthy(num);

      //Check and display the result
      if (checkResult)
         System.out.println(num + " is a Krishnamurthy number");
      else
         System.out.println(num + " is not a Krishnamurthy number");

   }
}

Output:

//Run: 1
Enter an integer: 145
145 is a Krishnamurthy number

//Run: 2
Enter an integer: 123
123 is not a Krishnamurthy number

We have created two different user-defined functions, one to calculate the factorial of a number and another to check the number for Krishnamurthy which is a boolean function.

---

Java Program to check Krishnamurthy number within the given Range

import java.util.Scanner;

public class KrishnamurthyProgram
{
   // main function
   public static void main(String[] args)
   {
      int lrRange, upRange;

      //create Scanner class object to take input
      Scanner scan = new Scanner(System.in);

      // take input from end-user
      System.out.print("Enter lower Range value: ");
      lrRange = scan.nextInt();
      System.out.print("Enter Upper Range value: ");
      upRange = scan.nextInt();

      System.out.println("The Krishnamurthy number between " + lrRange + " and " + upRange + " are: ");

      for (int i = lrRange; i <= upRange; i++)
      {
         if (isKrishnamurthy(i))
            System.out.print(i + " ");
      }
   }

   // boolean function to check Krishnamurthy Number
   public static boolean isKrishnamurthy(int num)
   {
      int sum = 0, lastDigit = 0;
      int temp = num;

      // iterating through all the digits
      while (temp != 0)
      {
         lastDigit = temp % 10;
         sum += factFunc(lastDigit);	//calling factFunc func for every digit
         temp /= 10;
      }

      // compare sum and number
      if (sum == num)
         return true;
      return false;
   }

   //user defined function to calculate the factorial
   public static long factFunc(int n)
   {
      long fact = 1;
      for (int i = 1; i <= n; i++)
         fact *= i;

      return fact;
   }
}

Output:

Enter lower Range value: 1
Enter Upper Range value: 1000
The Krishnamurthy number between 1 and 1000 are: 
1 2 145

As you can see, we did the same way by creating separate functions but here we took the user input for both the lower and upper range and called the function within those ranges to find all the possible Krishnamurthy number java.

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In this tutorial, we will learn about the ISBN (International Standard Book Number) and write a program to check for the ISBN Number in Java

ISBN number program in java.

ISBN is a 10-digit unique number that is is carried by almost each and every book. It is used to identify the book uniquely. With the help of ISBN, we can easily find a book. The ISBN is legal if 1*digit1 + 2*digit2 + 3*digit3 + 4*digit4 + 5*digit5 + 6*digit6 + 7*digit7 + 8*digit8 + 9*digit9 + 10*digit10 is divisible by 11.

The first nine digits of the ISBN number are used to represent the Title, Publisher, and Group of the book, and the last digit is used for checking whether ISBN is correct or not.

Example:

Let us consider a number: 1259060977
Check:
Sum = 1*10 + 2*9 + 5*8 + 9*7 + 0*6 + 6*5 + 0*4 + 9*3 + 7*2 + 7*1 = 209
Now divide the sum by 11 and see if the remainder obtained is zero or not.
rem = 209%11 = 0
Since, rem = 0, therefore 1259060977 is a legal ISBN number.

---

Steps to write Program for ISBN number Java

• First, take a 10-digit number input from the user.
• The second step is to check if the entered number is 10-digits or not because a number cannot be ISBN if it is not a 10-digit number. If it is not a 10-digit number then we will display an invalid message otherwise follow the steps below.
• For the sum, we need to multiply each digit by 1 to 10 from left to right.
• Lastly, divide the sum and check if the remainder is zero or not, if it is zero then the entered number is an ISBN number else it is not.

Now let us implement the above logic to check whether the number is an ISBN or not in java.

---

Java Program to check for ISBN Number

//Program to check the ISBN number in java

import java.io.*;

public class ISBNumberProgram
{
   public static void main(String[] args) throws IOException
   {
      long num;
      int sum = 0, i, t, d, dNumber;
      String numString;
     
      // User input
      InputStreamReader in = new InputStreamReader(System.in);
      BufferedReader br = new BufferedReader(in);
      
      System.out.print("Enter 10-digit ISBN number: ");
      num = Long.parseLong(br.readLine());

      //check if the entered digits are total 10 digits or not
      numString = "" + num;
      if (numString.length() != 10)
      {
         System.out.println("Invalid Number");
         return; //the program will terminate
      }

      // computing sum by iterating each digits
      for (i = 0; i < numString.length(); i++)
      {
         d = Integer.parseInt(numString.substring(i, i + 1));
         dNumber = i + 1;
         t = dNumber * d;
         sum += t;
      }

      //lastly check and display the result
      if ((sum % 11) != 0)
      {
         System.out.println(num+ " is an Illegal ISBN Number");
      }
      else
      {
         System.out.println(num+ " is a Legal ISBN Number");
      }
   }
}

Output: After execution following result will be displayed.

//Run: 1
Enter 10-digit ISBN number: 1259060977
1259060977 is a Legal ISBN Number

//Run: 2
Enter 10-digit ISBN number: 8417652579
8417562579 is an Illegal ISBN Number

You may create a separate user define function where you can pass the entered number and do the necessary calculation and at the end return the result to the main function. This is how you calculate the ISBN number java.

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In this section, we will learn about the evil number and the java program on evil numbers. We will write java code to check the given number for evil number.

What is Evil Number?

A number is said to be an evil number if it is a positive whole number that has an even number of 1’s in its binary expansion. Binary expansion refers to the binary representation of a number that is with 0(zero) and 1(one).

Odious numbers are opposite to evil numbers.

Example of evil number:

Input = 3
The binary value of 3 = 11. Since the 1’s are even, therefore 3 is an evil number.

Input = 23
The binary value of 23 = 10111. Since the 1’s are even, therefore 23 is an evil number.

Input = 4
The binary value of 4 = 100. Since the 1’s are odd, therefore 23 is not an evil number. But it is an odious number.

Now we know what is Evil number is, let us see Evil Number Program in Java with source code.

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Java program to check whether the given number is an evil number or not.

We will take a number and find its binary equivalent and store the binary value in a variable. Then we will check the number of 1’s present in that binary variable. If the number of 1’s is even then it is an evil number else the given number is not an evil number.

import java.util.Scanner;

public class EvilNumberProgram
{
   // user-defined method to check evil number
   public static boolean isEvil(int number)
   {
      // calling binaryConversion function by passing the number
      long binValue = binConversion(number);
      int count = 0;

      // iteration to increase the count value on every 1's
      while (binValue != 0)
      {
         if (binValue % 10 == 1)
            count++;

         binValue /= 10;
      }

     	// check for count for even value
      if (count % 2 == 0)
         return true;

      // if odd value than return false
      return false;
   }

   private static long binConversion(int num)
   {
      long binValue = 0;
      int remainder = 0;
      int i = 1;

      //iteration to convert the number into binary
      while (num != 0)
      {
         remainder = num % 2;
         binValue += remainder * i;

         num /= 2;
         i *= 10;
      }

      return binValue;
   }

   public static void main(String[] args)
   {
      // declaration of variables
      int num = 0;

      Scanner scan = new Scanner(System.in);
      System.out.print("Enter the positive number: ");
      num = scan.nextInt();

      // check the condition of returned value for evil number
      if (isEvil(num))
         System.out.println(num + " is an evil number");
      else
         System.out.println(num + " is not an evil number");

   }
}

Output: Evil Number Java.

//Run 1
Enter the positive number: 23
23 is an evil number

//Run 2
Enter the positive number: 4
4 is not an evil number

In the above java evil program, we created two user-defined functions, one for the conversion of an integer to binary and another one that checks the number of 1’s present in the binary number and returns the true-false value to the main function accordingly.

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In this tutorial, we will learn about the Duck number with examples and write a java program for duck numbers. Before that, you may go through the following topics in java.

• loops in java
• decision statement in java

What is a Duck Number?

A number is said to be a duck number if it is a positive integer number with zeroes in it. The digit zero (0) must not be present at the beginning of the number but can be present anywhere except the initial digit.

Example of duck number:

• 3210 is a duck number.
• 0183 is not a duck number because there is a zero present at the beginning of the number.
• 00132 is also not a dick number.

Now you have understood the Duck number, let us do a program to check duck numbers in java.

---

Java program to check whether a number is duck number or not

//Java Duck Number

import java.util.Scanner;

public class DuckNumberProgram
{
   public static void main(String[] args)
   {
      // variables
      int num, temp;
      boolean flag = false;

      Scanner sc = new Scanner(System.in);

      //user input
      System.out.print("Enter a positive integer: ");
      num = sc.nextInt();

      temp = num;

      //checking condition
      while (temp > 0)
      {
         if (temp % 10 == 0)
             flag = true;

         temp = temp / 10;
      }

      //checking for flag 
      if (flag)

         System.out.println(num + " is a Duck Number");

      else      
         System.out.println(num + " is not a Duck Number");

   }
}

Output:

//Run: 1
Enter a positive integer: 2015
2015 is a Duck Number

//Run: 2
Enter a positive integer: 00124
124 is not a Duck Number

//Run: 3
Enter a positive integer: 11245
11245 is not a Duck Number

You can create a separate Boolean function that will return true or false like the flag that is working in this program. Hope this article was helpful on Duck Number Program in Java

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In this section, we are going to learn about the magic number in Java and also how to find magic numbers in java.

What is Magic Number?

A number is said to be a magic number if the sum of its digits is calculated till a single digit is obtained by recursively adding the sum of its digits. And the single-digit which is obtained at the end must be 1, then the number is a magic number, otherwise, it is not a magic number.

Example: 1729 is a magic number.

Explanation:
1+7+2+9 = 19, the sum of the digit is 19, again
1+9 = 10
1+0 = 1, Therefore after the addition of digits, the last number we got is 1. Hence 1729 is a Magic Number.

---

Magic Number in Java

Let us see an example in java to check whether the number is a magic number or not. We will use a nested while loop in Java.

import java.util.Scanner;

public class MagicNumberProgram
{
   public static void main(String[] args)
   {
      int num, rem = 1, temp, sum = 0;
      Scanner sc = new Scanner(System.in);
      System.out.print("Enter number: ");
      num = sc.nextInt();
      temp = num;

      //checking the condition with nested while loop
      while (temp > 9)
      {
         while (temp > 0)
         {
            rem = temp % 10;
            sum = sum + rem;
            temp = temp / 10;
         }

         temp = sum;
         sum = 0;
      }

      if (temp == 1)
      {
         System.out.println(num + " is a Magic Number");
      }
      else
      {
         System.out.println(num + " is not Magic Number");
      }
   }
}

Output:

//Run: 1
Enter number: 1729
1729 is a Magic Number

//Run: 2 Enter number: 123
123 is not Magic Number

You can also create a separate Boolean function and return true or false to the main function after checking the number for magic in Java.

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In this tutorial, we will start with what is Buzz Number and Write a Java Program to check whether the number is Buzz Number or not.

Buzz Number

A Buzz number is one of the special numbers that end with 7 or is divisible by 7.

For example: 7, 17, 27, 37, etc are buzz numbers because they end with 7, and the numbers 7, 14, 21, 28, etc are also buzzed numbers because they are divisible by 7.

---

Program Approach to check the Buzz Number.

1. First take a number that needs to be checked for Buzz.

2. We then apply a condition to check the two conditions needed to check for the Buzz number.

• We check if the last digit is 7 or not with % operator (number % 10 == 7), which gives us the remainder.
• Then, we check the divisibility of a number by 7 with / operator (num / 7 == 0).

3. Both of these conditions are checked together in with || operator, in which if either one is true then || (or) operator returns a true value. Indicating the number is Buzz number.

4. Else the number is not a Buzz number.

---

Java Program to check whether the number is Buzz Number or not

import java.util.Scanner;

public class BuzzNumber
{
   public static void main(String args[])
   {
      Scanner sc = new Scanner(System.in);

      System.out.print("Enter a number to check for Buzz: ");
      int num = sc.nextInt();

      //Condition for Buzz number
      if (num % 10 == 7 || num % 7 == 0)
         System.out.println(num + " is a Buzz number.");
      else
         System.out.println(num + " is a not Buzz number.");
   }
}

Output:

//Run: 1
Enter a number to check for Buzz: 17
17 is a Buzz number.

//Run: 2
Enter a number to check for Buzz: 32
32 is a not Buzz number.

---

Java program to display all the Buzz number in a given Range

This is another example where we will print all the Buzz numbers in a given range in Java.

import java.util.Scanner;

public class BuzzNumber
{
   public static void main(String args[])
   {
      int lRange, uRange;

      Scanner sc = new Scanner(System.in);

      System.out.print("Enter the lower range: ");
      lRange = sc.nextInt();

      System.out.print("Enter the Upper range: ");
      uRange = sc.nextInt();

      System.out.print("List of all the buzz number between " + lRange + " and " + uRange);
      for (int i = lRange; i <= uRange; i++)
      {
         //Condition for Buzz number
         if (i % 10 == 7 || i % 7 == 0)
            System.out.println(i);
      }
   }
}

Output:

Enter the lower range: 0
Enter the Upper range: 50
List of all the buzz number between 0 and 50
7
14
17
21
27
28
35
37
42
47
49

You may create a separate boolean function to check for the Buzz number and return the number to the main function. Call the boolean function inside the for loop in the main function.

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In this tutorial, we will start by learning what is Sphenic Number and write a Java Program to check for the Sphenic Number.

Sphenic Number

A Sphenic Number is a positive integer n which is a product of exactly three distinct prime numbers. Or we can say that n is a sphenic integer if n = a * b * c (a, b, and c are three distinct prime numbers and their product is equal to n).

Example: 30, 42, 66, 70, 78, 102, 105, etc.

Explanation:

Input : 110
Output : Yes
Explanation : Factors of 110 are = 1, 2, 5, 10, 11, 22,55 and 110
              Take the smallest three prime factors: 2, 5, 11
               Product of these smallest prime factors:  2*5*11
                                                                                        = 110
                                                                                        = Input =110
               Hence the number is Sphenic Number.

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Java Program to Check if the Number is Sphenic Number or not

import java.util.*;

public class SphenicNumberExample1
{
   static boolean arr[] = new boolean[10000];

   static void findPrime()
   {
      Arrays.fill(arr, true);

      for (int p = 2; p * p < 10000; p++)
      {
         //if p is not changed, then it is a prime  
         if (arr[p])
         {
            for (int i = p * 2; i < 10000; i = i + p)
               arr[i] = false;
         }
      }
   }
 
   //checks if the given number is sphenic or not  
   static int isSphenic(int N)
   {
      int[] arr1 = new int[8];
      int count = 0, j = 0;

      for (int i = 1; i <= N; i++)
      {
         if (N % i == 0 && count < 8)
         {
            //increments the count by 1      
            count++;
            arr1[j++] = i;
         }
      }

      if (count == 8 && (arr[arr1[1]] && arr[arr1[2]] && arr[arr1[3]]))
         return 1;
      return 0;
   }

   //main function
   public static void main(String args[])
   {
      int n, result;

      findPrime();
      Scanner sc = new Scanner(System.in);

      System.out.print("Enter a number: ");
      n = sc.nextInt();

      result = isSphenic(n);

      if (result == 1)
         System.out.print(n + " is a sphenic Number.");
      else
         System.out.print(n + " is not a sphenic Number.");
   }
}

Output:

//First Execution
Enter a number: 30
30 is a sphenic Number.

//Second Execution
Enter a number: 165
165 is a sphenic Number.

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In this tutorial of Emirp Number in Java, we will write a program to check for the Emirp number in Java. Let us start by understanding, what is Emirp number.

Emirp Number

A number is said to be an Emirp number if it is a prime number and when reversed, the result formed is also a Prime Number. Emirp is backward for Prime, which indicates that a number, when formed backward, is also a prime number. Hence also known as twisted prime numbers.

Example: 13, 79, 199, 107 etc.

Explanation: Consider a Prime Number, 13
The reverse of 13: 31, which is also a prime number. Therefore, 13 is an Emirp Number.

---

Java Program to check for Emirp Number Using Function.

import java.io.*;
import java.util.*;

public class EmirpNumber
{
   //function to check for prime, returns boolean
   public static boolean isPrime(int n)
   {
      if (n <= 1)
         return false;

      for (int i = 2; i < n; i++)
      {
         if (n % i == 0)
            return false;
      }

      return true;
   }

   //function to check for emirp number, returns boolean
   public static boolean isEmirp(int n)
   {
      //calls isPrime function and checks for prime
      if (isPrime(n) == false)
         return false;

      int rev = 0;
      while (n != 0)
      {
         int digit = n % 10;
         rev = rev *10 + digit;

         n = n / 10;
      }

      //after reverse again checks for prime  
      return isPrime(rev);
   }

   //main function
   public static void main(String args[])
   {
      Scanner sc = new Scanner(System.in);

      System.out.print("Enter a number: ");
      int n = sc.nextInt();

      //Display accordingly
      if (isEmirp(n) == true)
         System.out.println(n + " is an Emirp number.");
      else
         System.out.println(n + " is not an Emirp number.");
   }
}

Output:

//First Run
Enter a number: 13
13 is an Emirp number.

//Second Run
Enter a number: 107
107 is an Emirp number.

//Third Run
Enter a number: 23
23 is not an Emirp number.

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In this tutorial, we will write an Autobiographical Number Program in Java and also learn what is Autobiographical Number.

Autobiographical Number

An autobiographical number is a number such that the first digit of it counts how many zeroes are there in it, the second digit counts how many ones are there, and so on. Basically, it counts the frequency of digits from 0 to 9 in order which they occur in a number.

Example: 1210 has 1 zero, 2 ones, 1 two, and 0 threes.
Some other examples include 2020, 21200, 3211000, 42101000, etc.

Explanation: Consider a number, 21200.

First, the sum of the digits: 2+1+2+0+0 = 5
Second, count the number of digits: 5
Since the sum of the digits is equal to the number of digits present in a number. Therefore, 21200 is an autobiographical number.

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Java Program to check if the given number is Autobiographical Number or not

import java.util.*;

public class AutobiographicalNumber
{
   public static void main(String args[])
   {
      int num, n;
      String str;
      boolean flag;
      Scanner sc = new Scanner(System.in);
      
      System.out.print("Enter the number: ");
      num = sc.nextInt();
      
      num = Math.abs(num);
      n = num;
      
      str = String.valueOf(num);

      int digitarray[] = new int[str.length()];
      for (int i = digitarray.length - 1; i >= 0; i--)
      {
         digitarray[i] = n % 10;
         n = n / 10;
      }

      flag = true;
      
      for (int i = 0; i < digitarray.length; i++)
      {
         int count = 0;
         for (int j = 0; j < digitarray.length; j++)
         {
            if (i == digitarray[j])
               count++;
         }

         if (count != digitarray[i])
         {
            flag = false;
            break;
         }
      }

      if (flag)
         System.out.println(num + " is an Autobiographical number.");
      else
         System.out.println(num + " is not an Autobiographical number.");
   }
}

Output:

//First Run
Enter the number: 1210
1210 is an Autobiographical number.

\\Second Run
Enter the number: 1410
1410 is not an Autobiographical number.

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