Utilities 25 : A nice maths trick

Hello everyone ! This nice program will play a nice maths trick on you, leaving you bewildered for a short time and curious for the rest period, to know its formula. Instructions will be provided by the program itself. Enjoy another nice program by ICSE Java.

Java Program :

import java.io.*;

class trick

{

  static BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

  static String garb;

  static int s;

  static void main()throws IOException

  {

      help();

      input();

      cal();

    }

    static void help()throws IOException

    {

        System.out.print("Welcome to Maths Magic.\n\nFor this trick, you need to think of a three digit number.");

        System.out.print("\n\nEnter when you are ready : ");

        garb=br.readLine();

        System.out.print("\fNow subtract the sum of digits from the original number.\n\nEx.: If you select 943, then subtract (9 + 4 + 3) from 943");

        System.out.print("\ni.e. 943 - (9 + 4 + 3) = 943 - 16 = 927.\n\nEnter when you are ready : ");

        garb=br.readLine();

    }

    static void input()throws IOException

    {

        s=0;

        System.out.print("\fNow enter any two of its digits, and I'll tell the third digit.\n\nEnter when you are ready : ");

        garb=br.readLine();

        try{

            System.out.print("\nEnter 1st digit : ");

            s=s+Integer.parseInt(br.readLine());

            System.out.print("\nEnter 2nd digit : ");

            s=s+Integer.parseInt(br.readLine());

        }

        catch(Exception e){

            System.out.print("\nError. Please try again : ");

            garb=br.readLine();

            System.out.print("\f");

            input();

        }

    }

    static void cal()

    {

        int i;

        for(i=0;i<=9;i++)

        if((s+i)%9==0)

        System.out.print("\nThe third digit is : "+i);

    }

}