In this tutorial you will learn about the Program to check Peterson Number in Java and its application with practical example.
In this tutorial, we will learn to create a Java Program to check Peterson Numbers in Java using Java programming.
Prerequisites
Before starting with this tutorial we assume that you are best aware of the following Java programming topics:
- Java Operators.
- Basic Input and Output function in Java.
- Class and Object in Java.
- Basic Java programming.
- If-else statements in Java.
- For loop in Java.
What is Peterson Number in Java
A number is called Peterson Number if sum of its factorials of each digit is equal to the sum of the number itself.
145 = 5! + 4! + 1!
145 = 120 + 24 +1
145 = 145
Explanation: factorial of
!5 = 5*4*3*2*1=120.
!4=4*3*2*1=24.
!1=1.
So sum of its factorial gives the number itself called Peterson.
Program to check Peterson Number in Java.
In this our program we will find given number is a Peterson number or not in using java. We would first declared and initialized the required variables. Next, we would prompt user to input the a number.Later we find number is Peterson number or not let’s have a look at the code.
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// Java program to find given number is Peterson number or not.. import java.util.Scanner; public class Peterson{ // static long[] factorial = new long[] { 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880}; public static void main(String args[]) { // Declaring and taking values form user.. Scanner scan = new Scanner(System.in); System.out.print("Enter any number: "); int number = scan.nextInt(); // checking condition for Peterson number.. if (Peterson(number)) System.out.println(number+ " is a Peterson number."); else System.out.println(number + " is not a Peterson number."); } //Creating a method to find Peterson number static boolean Peterson(int no) { int number = no; int sum = 0; while (no > 0) { //we get the last digit of the number int lastDigit = no % 10; sum += factorial[lastDigit]; no = no / 10; } return (sum == number); } } |
Output
Peterson Number
Not a Peterson number
In the above program, we have first declared and initialized a set variables required in the program.
- number= it will hold entered number.
- sum= it will hold sum of digit
- no = it will also hold value of number
- lastdigit= last digit of a number.
After declaring variables in the next statement user will be prompted to enter a value and which will be assigned to variable ‘number’.
And after that we check condition for Peterson number if condition get satisfied it means the given number is Peterson number if not then it is not Peterson number.
Logic Behind of Finding Peterson Number.
- First we take and initialize a number to (number).
- Find the last digit (last digit) of the given number by user.
- Find the factorial of all the digits.
- Add the factorial of all digits to (sum) variable as shown in image below.
- Repeat steps until find all the factors of given number.
- Compare sum with number if( sum==number). If they are equal, the given number is Peterson,
- else not.
