How to check bouncy numbers in Java

In this shot, we discuss how to check bouncy numbers in Java.

Bouncy numbers

A bouncy number has both an increasing and decreasing sequence in in a single number, as opposed to a number that only has one or the other.

Example: $15349 ,125431, 984567$ , etc.

For $15349$ , we can see that this number has an increasing sequence from $1$ to $5$ and a decreasing sequence from $5$ to $3$ . From $3$ to $9$ , it again has an increasing sequence. So, $15349$ is a bouncy number, as it has both increasing and decreasing sequences.

Code

Let’s look at the code snippet below.

import java.util.Scanner;
class Bouncy {
   public static void main(String[] args) {
       Scanner sc= new Scanner((System.in));
       System.out.println("Enter the number:-");
       int num= sc.nextInt();
       if(isBouncy(num)==true){
           System.out.println(num+" is a bouncy number");
       }else{
           System.out.println(num+" is not a bouncy number");
       }
   }
   static boolean isBouncy(int num)
   {
       boolean isIncreasing= true,isDecreasing=true;
       int temp= num;
       // check if number is ascending
       int prev= temp%10;
       while(temp!=0)
       {
           int rem = temp%10;
           if(rem > prev){
               isIncreasing=false;
               break;
           }
           prev= rem;
           temp/=10;
       }
       temp=num;
       prev= temp%10;
       while(temp!=0)
       {
           int rem = temp%10;
           if(rem < prev){
               isDecreasing=false;
               break;
           }
           prev= rem;
           temp/=10;
       }
        if(!isIncreasing && !isDecreasing){
            return  true;
        }else{
            return  false;
        }
   }
}

Enter the input below

Code input area

Explanation

In line 1, we import the java.util.Scanner class to read input from the user.
In line 7, we create a Scanner object to take the input number from the user and store that input in an integer num.
In line 8, we call the isBouncy() function, which, if it returns true, prints that the input number "is a bouncy number".
In lines 14 to 48, we define the isBouncy() function. In this function, we initialize two boolean flags, isIncreasing and isDecreasing, as true.
In lines 18 to 29, we check if all the digits of the given number are in ascending order or not. We run a loop and check if any digit is greater than the next digit, then set the isIncreasing flag as false.
In lines 30 to 42, we repeat the previous step, but this time we check for descending order and set the isDecreasing flag as false.
In line 43, we check both the flags, and the value is returned per the condition.

In this way, we can check bouncy numbers in Java.

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