# Repdigit Numbers in Java

A combination of repeated and digit, the term is. A repdigit, also known as a monodigit or a positional number system, is a natural number in recreational mathematics made up of repeated occurrences of the same digit (often implicitly decimal). These are a few examples, 99, 555, 1111, and 88888. Palindromic and multiples of repunits and repdigits are all numbers. In particular, the Mersenne primes and the repunit primes are two other well-known types of repdigits (which are repdigits when represented in the binary).

Repdigits are a representation of the number a B b 1 B 1 in base Y display style Y, where 0 x Y display style 0 x Y is the replicated digit and 1 y display style 1 y is the count of repetitions. For instance, the base 10 representation of the repdigit 99999 is 9 10 5 1 10 1 display style 7times frac 105-110-1.

Brazilian numbers are a subset of repdigits that can be represented as a repdigit in various bases but exclude the repdigit 11 and mono values (or all the numbers will be Brazilian). For instance, the repdigit 33 in base 8 makes the number 27 a Brazilian number. In contrast, the repdigit 118, which is not permitted under the description of Brazilian numbers, makes the number 9 not a Brazilian number.

Creating Java programmes and learning about repdigit numbers are covered in this section.

To determine whether the provided value is a repdigit value or not. The repdigit number program is widely tested in academic settings and Java code interviews.

## The Repdigit number

Repeated digits are abbreviated as repdigit. The sequence is A010785 from the OEIS. The repdigit is a numeric N that is equal and has the same number of digits inside its expression in base B.

Rep-units are the repdigits made up of repeated ones.

## Example for the repdigits numbers

If the number 777 has a base of 10, then it is a repdigit number. In a similar way, 2000 will become a repdigit number if the specified base is 7 and the number in question. Because 2000 can be expressed as 5555 in base 7.

The initial repdigit numbers are as follows:

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 111, 222, 333, 444, 555, 666, 777, 888, 999, 1111, 2222, 3333, 4444,5555, 6666, 7777, 8888, 9999 etc. can be possibly considered as the repdigit numbers.

## Finding a Repdigit Number: Steps

• Find each of the N digits in base B one by one.
• Every digit should be compared to its predecessor.
• Return false whether any value is not comparable to the previous digit.
• If not, return true.

Let's put the actions mentioned above into a Java program.

## Java Program for Repdigit Number

We entered the number N into the software below to see whether it was a repdigit value is base (B) or not.

Let the file name of the program is RepdigitNumberDemo.java

``````import java.util.Scanner;
public class RepdigitNumberDemo
{
// function to determine whether or if a particular value is indeed a Repdigit number
static boolean theRepdigitNumber(int number, int s)
{
// given the starting value of -1 since it is the lowest possible digit, variable saves the preceding digit.
int previous = -1;
// from right to left, traverse the specified number in a loop.
while (number != 0)
{
// determines the given number's last digit
int lastdigit = number % s;
// divides by base the given number (s)
number = number/s;
// if previous is not -1, then execute
if (previous != -1 && lastdigit != previous)
return false;
previous = lastdigit;
}
return true;
}
//It is the driver code
public static void main(String args[])
{
int number, s;
Scanner sc=new Scanner(System.in);
number = sc.nextInt();
s = sc.nextInt();
if(theRepdigitNumber(number, s))
{
System.out.print("This number is a repdigit.");
}
else
{
System.out.print("It is not a number with repdigits.");
}
}
} ``````

Output 1:

``````Please enter the number: 2000
This number is a repdigit.
``````

Output 2:

``````Please enter the number: 5555
``````Please enter the number: 66666