Sunny Number in Java

In this section, we will learn what is sunny numbers and how to create a Java program to find the sunny numbers. We will also create a Java program to find all the sunny numbers between the specified range.

Sunny Number

A number is called a sunny number if the number next to the given number is a perfect square. In other words, a number N will be a sunny number if N+1 is a perfect square.

Let's understand it through an example.

Sunny Number Example

Suppose, we have to check if 80 is a sunny number or not.

Given, N=80 then N+1 will be 80+1=81, which is a perfect square of the number 9. Hence 80 is a sunny number.

Let's take another number 10.

Given, N=10 then N+1 will be 10+1=11, which is not a perfect square. Hence 10 is not a sunny number.

Steps to Find Sunny Number

The logic is very simple. To find the sunny number, we need only to check whether N+1 is the perfect square or not.

Read or initialize a number (num).
Add 1 to the given number i.e. num+1.
Find the square root of num+1.
If the square root is an integer, the given number is sunny, else not a sunny number.

Sunny Number Java Program

SunnyNumberExample1.java

import java.util.*; public class SunnyNumberExample1 { //driver code public static void main(String args[]) { Scanner sc = new Scanner(System.in); System.out.print("Enter a number to check: "); //reading a number from the user int N=sc.nextInt(); //calling user-defined function isSunnyNumber(N); } //function checks whether the given is a perfect square or not static boolean findPerfectSquare(double num) { //finds the square root of the ggiven number double square_root = Math.sqrt(num); //if square root is an integer return((square_root - Math.floor(square_root)) == 0); } //function that checks whether the given number is Sunny or not static void isSunnyNumber(int N) { //checks N+1 is perfect square or not if (findPerfectSquare(N + 1)) { System.out.println("The given number is a sunny number."); } //executes if N+1 is not a perfect square else { System.out.println("The given number is not a sunny number."); } } }

Output 1:

Enter a number to check: 80
The given number is a sunny number.

Output 2:

Enter a number to check: 670
The given number is not a sunny number.

Let's create another Java program and find all the sunny numbers between a given range.

SunnyNumberExample2.java

import java.util.Scanner; public class SunnyNumberExample2 { //user-defined function that determines all the sunny numbers public static boolean isSunnyNumber(int number) { //determines the square root of number+1 using Math.sqrt() method if(Math.sqrt(number+1)%1 == 0) return true; else return false; } //driver code public static void main(String args[]) { //lr is lower range and ur is upper range int lr = 0, ur = 0; Scanner scan = new Scanner(System.in); System.out.print("Enter lower range: "); //reads an integer (lr) from the user lr = scan.nextInt(); System.out.print("Enter upper range: "); //reads an integer (ur) from the user ur = scan.nextInt(); System.out.println("The Sunny number from "+ lr + " to "+ ur+" are: "); for(int i=lr; i<=ur; i++) { //calling user-defined number if(isSunny(i)) System.out.print(i +" "); } } }

Output:

Enter lower range: 1
Enter upper range: 1000
The Sunny number from 1 to 1000 are: 
3 8 15 24 35 48 63 80 99 120 143 168 195 224 255 288 323 360 399 440 483 528 575 624

Sunny Number in Java

Sunny Number

Sunny Number Example

Steps to Find Sunny Number

All Answers

Sunny Number Java Program

Java Number Programs

This question belongs to these collections

Similar questions

need a help?

find thousands of online teachers now