Programming Examples

Java program to input a number and check whether it is a happy number or not


Write a program to input a number and check whether it is a happy number or not. If you iterate the process of summing the squares of the decimal digits of a number and if this process terminates in 1, then the original number is called a happy number. For example 7=> (72)=49=> (42+92)=97=>(92 +72)=130 =>(12 +32+02)=10 =>(12+02)= 1.

Solution

import java.util.*;
class HappyNumber
{
	public static void main(int n)
	{
		Scanner sc=new Scanner(System.in);
		int d,s,n;
		System.out.println(“Enter a number:”);
		n=sc.nextInt();
		do
		{
			s=0;
			while(n>0)
			{
				d=n%10;
				s+=d*d;
				n/=10;
			}
			n=s;
		}while(n>9);
		if(n==1)
			System.out.println(“Happy Number”);
		else
			System.out.println(“Not a Happy Number”);
	}
}
Output

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