BlueJ Program On Automorphic Number And Technical Analysis Of The Program

Today I will show you how to check a number whether it is automorphic number or not in BlueJ program. Before I proceed further, few clarifications are needed.

What is automorphic number

For any number we have to find the number of digits in it. From the square value of the number take digits equal to the number of digits of the number from the right side. If the original number and the part of the number are found equal on checking then the entered number is an automorphic number.

For example, 25 is an automorphic number. Number of digits in 25 is 2 and square value of 25 is 625. We have to take 2 extreme right digits from 625 as there are 2 digits in the original entered number. Two extreme right digits of 625 is 25 which matches with original number 25. So 25 is an automorphic number. Similarly 5 is also an automorphic number.

Codes of the automorphic number program

import java.io.*;
class Automorphic
{
int i,n,no,sqnum,rev=0,digit=0;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
public void getNumber() throws Exception
{
System.out.println("Enter the number:");
n=Integer.parseInt(br.readLine());
no=n;
do
{
digit++;
no=no/10;
} while(no!=0);

sqnum=n*n;
}
public void showResult()
{
do
{
rev=rev*10+sqnum%10;
sqnum=sqnum/10;
digit--;
if(digit==0)
break;
} while(true);

rev=reverse(rev);
if(n==rev)
System.out.println(n+" is an Automorphic number");
else
System.out.println(n+" is not an Automorphic number");
}
private int reverse(int n)
{
int r=0;
while(n!=0)
{
r=r*10+n%10;
n=n/10;
}
return r;
}
public static void main(String args[])throws Exception
{
Automorphic obj=new Automorphic();
obj.getNumber();
obj.showResult();
}
}

Technical analysis of the automorphic number program

Three functions are defined in this program. The function ‘public void getNumber()’ takes the number from user, counts the digits in it using a do while loop and calculate the square value of the number.

Within the body of another function ‘public void showResult()’ in this program, the digits from the square value is retrieved with proper checking so that the digits retrieved is equal to the number of digits in the original number. This retrieval of digits is performed using do while loop in this program.

The third defined function in this program ‘private int reverse(int n)’ defined in this class is to reverse a number, as from 625 on extracting two digits we will get 52 but we need it as 25.



Related Post: BlueJ Programs on Number