Question

Check whether a number is Unique Number or not using recursion.

( A Unique number is a positive integer (without leading zeros) with no duplicate digits. For example 7, 135, 214 , 5243 are all unique numbers whereas 33, 3121, 200 are not.)

				
					ENTER THE NUMBER
123456
123456 IS  AN UNIQUE NUMBER

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Code

				
					import java.util.Scanner;
public class UniqueNumber
{
    public static int CountDigits(long num,int digit,int noOfDigits)
    {
        if(num==0)
        {
            return noOfDigits; 
        }
        else
        {
            if(num%10==digit)
            {
                noOfDigits++;
            }
            return CountDigits(num/10,digit,noOfDigits);   
        }
    }

    public static void main()
    {
        int i=0,flag=0,count;
        long num=0;
        Scanner sc=new Scanner(System.in);
        System.out.println("ENTER THE NUMBER");
        num=sc.nextLong();
        System.out.println("Frequency of digits");

        for(i=0;i<=9;i++)
        {
            count=CountDigits(num,i,0);
            if(count>1)
            {
                flag=1; 
                break;
            }

        }
        if(flag==1)
        {
            System.out.println(num+" IS NOT AN UNIQUE NUMBER"); 
        }
        else
        {
            System.out.println(num+" IS  AN UNIQUE NUMBER"); 
        }
    }
}