Java: Check whether a number is a Duck Number or not
Java Numbers: Exercise-15 with Solution
Write a Java program to check whether a number is a Duck Number or not.
Note: A Duck number is a number which has zeroes present in it, but there should be no zero present in the beginning of the number. For example 3210, 7056, 8430709 are all duck numbers whereas 08237, 04309 are not.
Test Data
Input a number : 3210
Pictorial Presentation:
Sample Solution:
Java Code:
import java.util.Scanner;
public class Example15 {
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.print("Input a number : ");
String nstr = sc.nextLine();
int l = nstr.length();
int ctr = 0;
char chr;
for(int i=1;i<l;i++)
{
chr = nstr.charAt(i);
if(chr=='0')
ctr++;
}
char f = nstr.charAt(0);
if(ctr>0 && f!='0')
System.out.println("Duck number");
else
System.out.println("Not a duck number");
}
}
Sample Output:
Input a number : 3210 Duck number
Flowchart:

Java Code Editor:
Contribute your code and comments through Disqus.
Previous: Write a Java program check whether a number is an Automorphic number or not.
Next: Write a Java program to check two numbers are Amicable numbers or not.
What is the difficulty level of this exercise?
Test your Programming skills with w3resource's quiz.
Java: Tips of the Day
IsPowerOfTwo
Checks if a value is positive power of two.
To understand how it works let's assume we made a call IsPowerOfTwo(4).
As value is greater than 0, so right side of the && operator will be evaluated.
The result of (~value + 1) is equal to value itself. ~100 + 001 => 011 + 001 => 100. This is equal to value.
The result of (value & value) is value. 100 & 100 => 100.
This will value the expression to true as value is equal to value.
public static boolean isPowerOfTwo(final int value) { return value > 0 && ((value & (~value + 1)) == value); }
Ref: https://bit.ly/3sA5d4I
- Weekly Trends
- Python Interview Questions and Answers: Comprehensive Guide
- Scala Exercises, Practice, Solution
- Kotlin Exercises practice with solution
- MongoDB Exercises, Practice, Solution
- SQL Exercises, Practice, Solution - JOINS
- Java Basic Programming Exercises
- SQL Subqueries
- Adventureworks Database Exercises
- C# Sharp Basic Exercises
- SQL COUNT() with distinct
- JavaScript String Exercises
- JavaScript HTML Form Validation
- Java Collection Exercises
- SQL COUNT() function
- SQL Inner Join
We are closing our Disqus commenting system for some maintenanace issues. You may write to us at reach[at]yahoo[dot]com or visit us at Facebook