Duck Number in C# with Examples

In this article, I am going to discuss How to Implement the Duck Number Program in C# with Examples. Please read our previous article where we discussed How to Remove Duplicate Elements from an array in C# with two different approaches. Here, in this article, first, we will learn what is a Duck Number and then we will see how to implement the Duck Number program using the C# language.

What is a Duck Number?

A Duck number is a positive number that has zero (0) present in it. It may contain more than one 0 as an element but not as a leading element only. 0 should be present somewhere in the middle or as the last element of the digit. E.g.: 403,4002,43320,039830,034043 are all examples of duck number.

Condition: If a number has only led 0 as an element, then it will not be considered as a duck number. E.g.: 0432,0229,0643 are not examples of duck numbers.

How to Implement Duck Number in C#?

In this approach, we will convert integer numbers as string types and then extract each character one by one and check whether it equals ‘0’ or not.

Step1: convert entered value as a string.
Step2: Initialize a variable called ctr to store the value of the count of element ‘0’ in the string.
Step3: Using for loop we will take one by one character starting from index 1(we are not interested at index 0 because we duck number has 0’s in between or at last) and check for the ‘0’ element if it is equal to ‘0’ then simply increment the value of ctr.

Duck Number Program using C#

using System;
public class CheckDuckNo
{
    public static void Main (string[]args)
    {
        Console.WriteLine ("Enter a number to check whether it is a duck no. or not");
        int number = Convert.ToInt32 (Console.ReadLine ());

        String strNo = number.ToString ();

        //lenght of string
        int l = strNo.Length;

        //to count available no. of zeros
        int ctr = 0;

        //To store the characters one by one in the string
        char chr;

        for (int i = 1; i < l; i++)
        {
         chr = strNo[i];
         if(chr == '0')
         {
             ctr++;
             break;
         }
        }

        char f = strNo[0];

        if (ctr > 0 && (f == '0' || f != '0'))
            Console.Write ("Duck No.");
        else
            Console.Write ("Not a duck No.");
    }
}

Output:

Time Complexity: 0(n): As we are traversing the character array (string) only once.

How to find all the duck numbers between 1 to 100?

The following C# program shows how to find all the duck numbers between 1 to 100.

using System;
public class CheckDuckNo
{
  public static void Main (string[]args)
  {
        int dno, dkno, r, flg;
        flg = 0;
        Console.WriteLine ("Find Duck Numbers between 1 to 100: \n");
        Console.WriteLine ("The Duck numbers are: ");

        for (dkno = 1; dkno <= 100; dkno++)
        {
         dno = dkno;
         flg = 0;
    	    while(dno > 0)
         {
             if(dno % 10 == 0)
             {
              flg = 1;
              break;
             }
             dno /= 10;
         }
         if(dkno > 0 && flg == 1)
         {
             Console.Write (" " + dkno);
         }
        }
    }
}

Output:

In the next article, I am going to discuss Disarium Number in C# with Examples. Here, in this article, I try to explain How to Implement the Duck Number Program in C# and I hope you enjoy this article.