What is an Automorphic Number?
If the square of a number ends with the number itself, it is considered to be automorphic.
For Example:
25 is an automorphic number, as the square of 25 = 625 (ends with 25).
5^2 = 25
6^2 = 36
76^2 = 5776
Sequence of automorphic numbers: 1, 5, 6, 25, 76, 376, ..
Write a program to verify or check whether a given number is automorphic or not using Java
<![CDATA[import java.util.Scanner;
public class AutomorphicNumber
{
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.println(
"*** Automorphic number ***\n");
// Enter a number :
long num = in.nextLong();
long sqNum = num*num;
String strNum = Long.toString(num);
String square = Long.toString(sqNum);
String result =
( square.endsWith(strNum) )?
"Automorphic":"Not Automorphic";
System.out.println(" Number "
+num+" is "+result);
}
}]]>
Write a program to find all the automorphic numbers in a range
<![CDATA[/*
Description: The code finds all automorphic numbers in given range [1-N]
*/
import java.math.BigInteger;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Scanner;
public class AutomorphicNumbers{
public static void main(String...arg){
try {
String s=new Scanner(System.in). nextLine();
BigInteger N=new BigInteger(s), TEN=BigInteger.valueOf(10);
HashSet<String> set=new HashSet< String>();
int j=1; String s1="", s2="";
for(int i=0; i<10; i++){
boolean find=false;
BigInteger s1B=new BigInteger (i+s1), s2B=new BigInteger(i+s2);
if(N.compareTo(s1B)<0 && N. compareTo(s2B)<0) break;
if((""+s1B.pow(2)).endsWith(i+s1)){
s1=i+s1;
find=true;
}
if((""+s2B.pow(2)).endsWith(i+s2)){
s1=i+s2;
s1B=s2B;
find=true;
}
if(find){
if(N.compareTo(s1B)>=0&&!(j==1&&i==0)) set.add(s1);
if(!(j==1&&i<2)){
s2=((TEN.pow(j-1)). multiply(TEN)).add(BigInteger.ONE).subtract(s1B).toString();
if (N.compareTo(new BigInteger(s2))>=0) set.add(s2);
while(s2.length()<j)
s2=0+s2;
i=0; j++;
}// end if(!(j==1&&o<2))
}// end if(find)
}// end for
// display result:
System.out.printf("In range [1-%s] the automorphic numbers are:%n", s);
set.stream().sorted(Comparator. comparing(String::length).thenComparing(String::compareTo)).forEach(System.out::println);
} catch(NumberFormatException e){
System.out.println("Wrong input. Try again!");
}
}
}
]]>
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