Question

Print Kaprekar number in given range.
(A Kaprekar number is a number whose square when divided into two parts and such that the sum of parts is equal to the original number and none of the parts has value 0.)

ENTER A NUMBER: 45
45 IS A KAPREKAR NUMBER
45*45 = 2025 and 20 + 25 is 45

ENTER A NUMBER: 10
10 IS NOT A KAPREKAR NUMBER
10*10 = 100. It is not a Kaprekar number even if
sum of 100 + 0 is 100 because none of the parts should have value 0.

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Code

import java.util.Scanner;
public class kaprekarNumberInGivenRange
{
    public static void main()
    {

        int len=0,sum=0,firstPart=0,secondPart=0,i=0,lowerRange=0,upperRange=0;
        String sq="";
        Scanner sc=new Scanner(System.in);
        System.out.print("ENTER A LOWER RANGE:");
        lowerRange=sc.nextInt();
        System.out.print("ENTER A UPPER RANGE:");
        upperRange=sc.nextInt();

        System.out.println("KAPREKAR NUMBERS:");
        for(i=lowerRange;i<=upperRange;i++)
        {
            if(i<=3)
            {
                if(i==1)
                {
                    System.out.print(i+" ");
                }
            }
            else
            {
                sq=Integer.toString((i*i));
                len=sq.length();
                firstPart=Integer.parseInt(sq.substring(0,(len/2)));
                secondPart=Integer.parseInt(sq.substring((len/2),len));
                sum=firstPart+secondPart;

                if(sum==i &&(firstPart!=0)&&(secondPart!=0))
                {
                    System.out.print(i+" ");

                }
            }

        }

    }
}