Class happy 1/3/* * A Happy number is a number for which sum of squares of * digits finally comes out o be 1. * For Example: 139 * 1. 139 : 1 + 9 +81 = 91 * 2. 91 : 81 + 1 = 82 * 3. 82 : 64 + 4 = 68 * 4. 68 : 36 + 64 = 100 * 5. 100 : 1 + 0 +0 = 1 *

* Number of steps =5 *

* CLASS NAME : happy * DATA MEMBERS : n TO STORE THE NUMBER * FUNCIONS : * happy() : constructor to assign 0 to n * void getnum(int nn) : to assign parameter value to n * int power(int nn) :to return square of a number * int sumOfSquares(int nn) :returns sum of square of digits of a number * void ishappy() :to check if the given number is happy or not *

* Also find the number of steps required in the process for each number. * Also define the main() function to exeute the program by creating object. */

import java.io.*;public class happy { int n; public happy() //default constuctor { n=0;//initialing data member }

DataInputStream d=new DataInputStream(System.in);

public void getnum(int nn)//method to assign inputed value to n { n=nn; }

public int power(int nn)//to find and return square of a number { int p=nn*nn; return p; }

public int sumOfSquares(int nn)//to calculate sum of square { int m=nn;//creating dummy variable int r=0;

May 27, 2014 9:58:23 PM

Class happy (continued) 2/3 int ps=0;//to store sum of squares int t=0; System.out.print(nn+"\t="); //to print the process(only for understaning) while(m>0) { r=m%10; t=power(r); ps=ps+t;//calculating sum m=m/10;//updating loop variable System.out.print("\t"+t+( m>0 ? "\t+":" " )); //to print the process(only for understaning) } System.out.println(); return ps;//returning sum of squares of the digits }

public void ishappy() { int mm=n; int c=0;//counter to cont no of steps taken do { mm=sumOfSquares(mm); c++; }while(mm>9); //checking if sum of square is single digit

if(1==mm)//checking if final sum is equal to 1 { System.out.println("It is a happy number"); System.out.println("No of steps = "+c); //printing number of steps System.out.println(); } else { System.out.println("It is not a happy number"); } } /* * PROCESS AND LOGIC * 1) We find the sum of squares of the digits of the number. * 2) If the sum is not single digit then we repeat step 1. * For this we use the do while loop(we don't use only while * because the number entered at the first instance may itself * be sigle digit).We repeat this using the loop till the * sum(mm) is reduced to a single digit. * 3) Then we check if the sum is one or not and then display the * appropriate message. *

* We do not use the member variable but instead create a dummy * variable mm to not to alter n.

May 27, 2014 9:58:24 PM

Class happy (continued) 3/3 */

public void main()throws IOException { System.out.println("Enter a number"); int nn=Integer.parseInt(d.readLine());//inputing number System.out.println(); happy ob1=new happy();//creating object ob1.getnum(nn);//calling function via object ob1 ob1.ishappy();//calling function via object ob1 }//end of main

}//end of class

May 27, 2014 9:58:24 PM