# Check Whether a number is Duck Number or not

• Difficulty Level : Basic
• Last Updated : 15 Jun, 2022

A Duck number is a positive number which has zeroes present in it, For example 3210, 8050896, 70709 are all Duck numbers. Please note that a numbers with only leading 0s is not considered as Duck Number. For example, numbers like 035 or 0012 are not considered as Duck Numbers. A number like 01203 is considered as Duck because there is a non-leading 0 present in it.

Examples :

Input : 707069
Output : It is a duck number.
Explanation: 707069 does not contains zeros at the beginning.

Input : 02364
Output : It is not a duck number.
Explanation: in 02364 there is a zero at the beginning of the number.

## C++

 `// C++ Program to check whether` `// a number is Duck Number or not.` `#include ` `using` `namespace` `std;`   `// Function to check whether` `// given number is duck number or not.` `bool` `check_duck(string num)` `{` `    ``// Ignore leading 0s` `    ``int` `i = 0, n = num.length();` `    ``while` `(i < n && num[i] == ``'0'``)` `        ``i++;`   `    ``// Check remaining digits` `    ``while` `(i < n) {` `        ``if` `(num[i] == ``'0'``)` `            ``return` `true``;` `        ``i++;` `    ``}`   `    ``return` `false``;` `}`   `// Driver Method` `int` `main(``void``)` `{` `    ``string num = ``"1023"``;` `    ``if` `(check_duck(num))` `        ``cout << ``"It is a duck number\n"``;` `    ``else` `        ``cout << ``"It is not a duck number\n"``;`   `    ``return` `0;` `}`

## Java

 `// Java Program to check whether a` `// number is Duck Number or not.`   `import` `java.io.*;` `class` `GFG {`   `    ``// Function to check whether` `    ``// the given number is duck number or not.` `    ``static` `boolean` `check_duck(String num)` `    ``{` `        ``// Ignore leading 0s` `        ``int` `i = ``0``, n = num.length();` `        ``while` `(i < n && num.charAt(i) == ``'0'``)` `            ``i++;`   `        ``// Check remaining digits` `        ``while` `(i < n) {` `            ``if` `(num.charAt(i) == ``'0'``)` `                ``return` `true``;` `            ``i++;` `        ``}`   `        ``return` `false``;` `    ``}`   `    ``// Driver Method` `    ``public` `static` `void` `main(String args[]) ``throws` `IOException` `    ``{` `        ``String num = ``"1023"``;` `        ``if` `(check_duck(num))` `            ``System.out.println(``"It is a duck number"``);` `        ``else` `            ``System.out.println(``"It is not a duck number"``);` `    ``}` `}`

## Python

 `# Python program to check whether a number is Duck Number or not.`   `# Function to check whether ` `# the given number is duck number or not.` `def` `check_duck(num) :`   `    ``# Length of the number(number of digits)` `    ``n ``=` `len``(num) ` `   `  `    ``# Ignore leading 0s` `    ``i ``=` `0` `    ``while` `(i < n ``and` `num[i] ``=``=` `'0'``) :` `        ``i ``=` `i ``+` `1`   `    ``# Check remaining digits` `    ``while` `(i < n) : ` `        ``if` `(num[i] ``=``=` `"0"``) :` `            ``return` `True` `        ``i ``=` `i ``+` `1`   `    ``return` `False` `    `    `# Driver Method` `num1 ``=` `"1023"` `if``(check_duck(num1)) :` `    ``print` `"It is a duck number"` `else` `:` `    ``print` `"It is not a duck number"`   `# Write Python3 code here`

## C#

 `// C# Program to check whether a ` `// number is Duck Number or not.` `using` `System;`   `class` `GFG {` `    `  `    ``// Function to check whether ` `    ``// the given number is duck` `    ``// number or not.` `    ``static` `bool` `check_duck( String num)` `    ``{` `        `  `        ``// Ignore leading 0s` `        ``int` `i = 0, n = num.Length;` `        ``while` `(i < n && num[i] == ``'0'``)` `            ``i++;`   `        ``// Check remaining digits` `        ``while` `(i < n) {` `            ``if` `(num[i] == ``'0'``)` `                ``return` `true``;` `            ``i++;` `        ``}`   `        ``return` `false``;` `    ``}` `    `    `    ``// Driver Method` `    ``public` `static` `void` `Main()` `    ``{` `        `  `        ``String num1 = ``"1023"``; ` `        `  `        ``// checking number1` `        ``if``( check_duck(num1))` `            ``Console.Write(``"It is a "` `                      ``+ ``"duck number"``);` `        ``else` `            ``Console.Write(``"It is not "` `                    ``+ ``"a duck number"``);` `    ``}` `}`   `// This code is contributed by` `// nitin mittal.`

## Javascript

 ``

Output :

`It is a duck number.`

Time Complexity: O(n) where n is length of string.

Auxiliary Space: O(1)

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