What Is Happy Number In Java And Check Number Is Happy Or Sad?

7:00 PM
Dear reader this Article is all about happy and sad numbers. in this post, I will teach you what is a Happy and Sad number with the help examples, and also we perform an operation of the program to check happy number in java.



let's Understand what is Happy Number in java:-

Definition:- Any positive integer which is starting from 1 (Greater than 0), and replaces the number by the sum of the squares of its digits, and repeats the all process until the final result becomes 1.


 For Example check 28 is Happy or Not?
22 + 82 = 4+64 =68
62+82 = 36+64= 100
12+02+02 = 1+0+0= 1

 we get 1 that's means this number is a Happy Number.
NOTE:- if we are not getting 1 that means the number is sad Number.


Here is the list of Happy no under 100:- 1, 7, 10, 13, 19, 23, 28, 31, 32, 44, 49, 68, 70, 79, 82, 86, 91, 94, 97, and also 100.

Java Code:-

1:  import java.util.Scanner;  
2:  public class HappyNos {  
3:  static boolean ishappy(int n)  
4:  {  
5:  while(n>9){  
6:  int sum=0;  
7:  while(n!=0){  
8:  int r=n%10;  
9:  sum=sum+r*r;  
10:  n=n/10;  
11:  }  
12:  n=sum;  
13:  }  
14:  return n==1||n==7;  
15:  }  
16:  static void happyno(int n){  
17:  System.out.println("Happy nos are");  
18:  for(int i=1;i<=n;i++){  
19:  if(ishappy(i)){  
20:  System.out.print(i+ " ");  
21:  }  
22:  }  
23:  }  
24:  static int counthappy(int n){  
25:  int count=0;  
26:  for(int i=1;i<=n;i++){  
27:  if(ishappy(i)){  
28:  count++;  
29:  }  
30:  }  
31:  return count;  
32:  }  
33:  static int sumhappy(int n){  
34:  int sum=0;  
35:  for(int i=1;i<=n;i++){  
36:  if(ishappy(i)){  
37:  sum=sum+i;  
38:  }  
39:  }  
40:  return sum;  
41:  }  
42:  public static void main(String[] args) {  
43:  Scanner sc=new Scanner(System.in);  
44:  System.out.println("Enter the no");  
45:  int n=sc.nextInt();  
46:  boolean b=ishappy(n);  
47:  if(b)  
48:  System.out.println("Happy no");  
49:  else  
50:  System.out.println("Not happy no");  
51:  happyno(n);  
52:  int cnt=counthappy(n);  
53:  System.out.println("\ntotal happy are "+cnt);  
54:  int sm=sumhappy(n);  
55:  System.out.println("total happy are "+sm);  
56:  }  
57:  }

Output:-

 Enter the no  
 21  
 Not happy no  
 Happy nos are  
 1 7 10 13 19  
 total happy are 5  
 total happy are 50

Explanation of some important lines:-
  • first of all, we create a class.
  • creating a static method (ishappy).
  • in this method, we are using a while loop.
  • create a variable.
  • after then again using while loop.
  • return values after the crack loop.
  • create one more static method (happyno).
  • used println method for printing happy numbers.
  • using for loop.
  • using if condition.
  • create one more static method (counthappy).
  • using for loop.
  • one more static method (sumhappy).
  • run for loop.
  • create the main method.
  • import Scanner class.
  • use if else condition.
  • create a variable and put counthappy method.
  • printing the total number of count.
  • create one more variable and put the sumhappy method.
  • print the total happy number sum.

Admin Words:- I am tried to solve all these happy number in java. This program will help you to understand the sad and happy number in java. 

If you find any error in this program reminds me of the comment. and if you have any questions regarding this program please feel free to ask in the comment below of this post.

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