# Program to check for a Happy Number.

Happy Number – Replace the number by the sum of the squares of its digits, and repeat the process. At the end, if the number is equals to 1 then it is a Happy Number, or it loops endlessly in a cycle that does not include 1 (if it is not a happy number then this process will end at 4).

For example:

23 is a Happy Number

23 :> 2^2 + 3^2 = 13
13 :> 1^2 + 3^2 = 10
10 :> 1^2 + 0 = 1

As we reached to 1, 23 is a Happy Number.

42 is a UnHappy Number

42 :> 4^2 + 2^2 = 20
20 :> 2^2 + 0 = 4

As we reached to 4, 42 is a UnHappy Number.

## C

#include<stdio.h>

int main()
{
int num,temp,sum=0;

printf("Enter a Number : ");
scanf("%d",&num);

while(sum!=1 && sum!=4)
{
sum=0;

while(num>0)
{
temp=num%10;
sum+=(temp*temp);
num=num/10;

}
num=sum;
}

if(sum==1)
printf("Happy Number");
else
printf("UnHappy Number");

return 0;
}

## C++

#include<iostream.h>

int main()
{
int num,temp,sum=0;

cout<<"Enter a Number : ";
cin>>num;

while(sum!=1 && sum!=4)
{
sum=0;

while(num>0)
{
temp=num%10;
sum+=(temp*temp);
num=num/10;

}
num=sum;
}

if(sum==1)
cout<<"Happy Number";
else
cout<<"UnHappy Number";

return 0;
}

## Java

import java.util.Scanner;

class HappyNumber
{

public static void main(String args[])
{
int num;
int temp;
int sum = 0;

Scanner sc= new Scanner(System.in);

System.out.print("Enter a number : ");
num = sc.nextInt();

while (sum != 1 && sum != 4)
{
sum = 0;

while (num > 0)
{
temp = num % 10;
sum += (temp * temp);
num = num / 10;

}
num = sum;
}

if (sum == 1)
{
System.out.print("Happy Number");
}
else
{
System.out.print("UnHappy Number");
}

}
}

## C#

class HappyNumber
{
public static void Main()
{
int num;
int temp;
int sum = 0;

Console.Write("Enter a number : ");
while (sum != 1 && sum != 4)
{
sum = 0;

while (num > 0)
{
temp = num % 10;
sum += (temp * temp);
num = num / 10;

}
num = sum;
}

if (sum == 1)
{
Console.Write("Happy Number");
}
else
{
Console.Write("UnHappy Number");
}
}
}

## Python

sum = 0

num = int(input("Enter the number: "))

while (sum != 1 and sum != 4):
sum = 0
while (num > 0):
temp = num % 10
sum += (temp * temp)
num = num // 10
num = sum

if (sum == 1):
print("Happy Number")
else:
print("UnHappy Number")
OUTPUT:

(1st Run)

Enter the number: 19
Happy Number

(2nd Run)

Enter the number: 165
UnHappy Number