package Maths;

/**
 * A number is said to be an Automorphic, if it is present in the last digit(s) of its square.
 * Example- Let the number be 25, its square is 625.
 * Since, 25(The input number) is present in the last two digits of its square(625),
 * it is an Automorphic Number.
 */
import java.io.*;

public class AutomorphicNumber
{
 //returns True if the number is a Automorphic number and False if it is not an Automorphic number
 public static boolean isAutomorphic(int n)
 {
 int m, c, r, p, k; c = 0;
 /** m = Temporary variable to store a copy of the number entered by the user.
 * n = The number entered by the user
 * c = Count the digits of the number entered by user.
 * p = To calculate the square of the number.
 * k = Support variable to count the digits of the number
 */
 double s;
 m = n;
 p = m * m; //Calculating square of the number
 do
 {
 k = n / 10;
 c = c + 1; //Counting the digits of the number entered by user.
 n = k;
 }
 while(n != 0);
 s = Math.pow(10, c); 
 r = p %(int)s;
 if(m == r) //Checking if the original number entered is present at the end of the square
 {
 return true;
 }
 else
 {
 return false;
 }
 }

 /** Method to check if number is Automorphic Number or Not
 * 1) Input - Enter a Number: 25
 * Output - It is an Automorphic Number.
 * 2) Input - Enter a Number: 7
 * Output - It is not an Automorphic Number.
 */
 public static void main(String args[]) throws IOException
 {
 BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
 System.out.println("Enter a Number: ");
 int n=Integer.parseInt(br.readLine());
 if(isAutomorphic(n))
 {
 System.out.println("It is an Automorphic Number.");
 }
 else
 {
 System.out.println("It is not an Automorphic Number.");
 }
 }
}