Automorphic Number in Java

In this tutorial we will learn about what is automorphic number in java and write Java program for automorphic number in java.

What is automorphic number in java

A number is called an automorphic number if and only if the square of the given number ends with the same number itself.

For example 5 , 6, 25 are automorphic numbers because their square is 15 , 36 and 625 respectively  and last digit are same as number itself .

Java program for automorphic number

In this  automorphic number program in java we take input from user to check given number is automorphic or not with the help of scanner . We use following steps to check given number is automorphic number or not .

1. take input from user num
2. calculate square sqr of num
3. count digit of num
4. now take last count digit of square sqr of num and compare with num
5. if last digit are equal to num then given number is automorphic number .

public class AutomorphicNumber {
	
	public static void main(String[] args) {
		
	Scanner in = new Scanner(System.in);
        System.out.println("Enter a number");
        int num = in.nextInt();
 
        int count=0, sqr = num*num;
        int temp =num;  
 
        //count digit of number 
        while(temp>0){
        	count++;
            temp=temp/10;
        }
 
        //taking last count digit of sqr of num
        int lastSquareDigits = (int) (sqr%(Math.pow(10,count)));
 
        if(num == lastSquareDigits)
            System.out.println("Given number is Automorphic number");
        else
            System.out.println("Given number is not an Automorphic number");
     }
		
	}

Output :

Enter a number
5
Given number is Automorphic number

Now we will write one more java program to check given number is automorphic number using different  logic . In this program we write a function to check automorphic number and steps as following

1. take input from user
2. call function isAutomorphicNumber(int num)
3. calculate square sqrt of  num
4. Now iterate while loop till num is > 0
5. In loop we compare last digit of num and sqrt
6. if last digit does not match then we return false
7. if last digit is equal then num and sqrt divide by 10 and assign result in num and sqrt respectively .
8. if num matches with last digit of sqrt then it will retun true at the end .

 

import java.util.Scanner;

public class AutomorphicNumber2 {
	
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
	    System.out.println("Enter a number");
	    int num = in.nextInt();
	    
	    if(isAutomorphicNumber(num))
            System.out.println("Given number is Automorphic number");
        else
            System.out.println("Given number is not an Automorphic number");
	    
	}

    public static boolean isAutomorphicNumber(int num){
    	int sqrt = num * num;
    	while ( num > 0) {
    		//compare last digit of num and sqrt 
			if ( num %10 != sqrt%10 ){ 
				return false ;
			}
			
			num = num /10;
			sqrt = sqrt/10;
		}
		return true;
    }
}

Output :

Enter a number
6
Given number is Automorphic number

Java Program to Find all Automorphic Numbers in the Interval

Here we write java program to find all automorphic number in given range .

import java.util.Scanner;

public class AutomorphicNumberForRange {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
	    System.out.println("Enter a lower range value");
	    int low = in.nextInt();
	    
	    System.out.println("Enter a upper range value");
	    int upper  = in.nextInt();
	    for (int i = low; i <= upper; i++) {
	    	  if(isAutomorphicNumber(i))
	              System.out.println( i +"  ");	
		}
	}
	
	
    public static boolean isAutomorphicNumber(int num){
	  int count=0, sqr = num*num;
      int temp =num;  

      //count digit of number 
      while(temp>0){
      	count++;
          temp=temp/10;
      }

      //taking last count digit of sqr of num
      int lastSquareDigits = (int) (sqr%(Math.pow(10,count)));
      
      return num == lastSquareDigits;
    }
	
}

Output:

Enter a lower range value
1
Enter a upper range value
100
1  
5  
6  
25  
76

In this tutorial we have written java  program for automorphic number using different logic . you can learn java coding program for interview preparation .