# Check if the given decimal number has 0 and 1 digits only

Given an integer n, the task is to check whether n is in binary or not. Print true if n is the binary representation else print false.

Examples:

Input: n = 1000111
Output: true

Input: n = 123
Output: false

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Method #1: Using Set First add all the digits of n into a set after that remove 0 and 1 from the set, if the size of the set becomes 0 then the number is in binary format.

Below is the implementation of the above approach:

## C++

 `// C++ program to check whether the given number ` `// is in binary format ` `#include ` `using` `namespace` `std; ` `    ``// Function that returns true if given number ` `    ``// is in binary format  i.e. number contains ` `    ``// only 0's and/or 1's ` `    ``bool` `isBinary(``int` `number) ` `    ``{ ` `        ``set<``int``> set; ` `  `  `        ``// Put all the digits of the number in the set ` `        ``while` `(number > 0) { ` `            ``int` `digit = number % 10; ` `            ``set.insert(digit); ` `            ``number /= 10; ` `        ``} ` `  `  `        ``// Since a HashSet does not allow duplicates so only ` `        ``// a single copy of '0' and '1' will be stored ` `        ``set.erase(0); ` `        ``set.erase(1); ` `  `  `        ``// If the original number only contained 0's and 1's ` `        ``// then size of the set must be 0 ` `        ``if` `(set.size() == 0) { ` `            ``return` `true``; ` `        ``} ` `        ``return` `false``; ` `    ``} ` `  `  `    ``// Driver code ` `    ``int` `main() ` `    ``{ ` `        ``int` `n = 1000111; ` `        ``if``(isBinary(n)==1) ` `            ``cout<<``"true"``<

## Java

 `// Java program to check whether the given number ` `// is in binary format ` `import` `java.util.HashSet; ` `import` `java.util.Set; ` ` `  `class` `GFG { ` ` `  `    ``// Function that returns true if given number ` `    ``// is in binary format  i.e. number contains ` `    ``// only 0's and/or 1's ` `    ``static` `boolean` `isBinary(``int` `number) ` `    ``{ ` `        ``Set set = ``new` `HashSet<>(); ` ` `  `        ``// Put all the digits of the number in the set ` `        ``while` `(number > ``0``) { ` `            ``int` `digit = number % ``10``; ` `            ``set.add(digit); ` `            ``number /= ``10``; ` `        ``} ` ` `  `        ``// Since a HashSet does not allow duplicates so only ` `        ``// a single copy of '0' and '1' will be stored ` `        ``set.remove(``0``); ` `        ``set.remove(``1``); ` ` `  `        ``// If the original number only contained 0's and 1's ` `        ``// then size of the set must be 0 ` `        ``if` `(set.size() == ``0``) { ` `            ``return` `true``; ` `        ``} ` `        ``return` `false``; ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `main(String a[]) ` `    ``{ ` `        ``int` `n = ``1000111``; ` `        ``System.out.println(isBinary(n)); ` `    ``} ` `} `

## Python3

 `# Python 3 program to check whether  ` `# the given number is in binary format ` ` `  `# Function that returns true if given  ` `# number is in binary format i.e. number  ` `# contains only 0's and/or 1's ` `def` `isBinary(number): ` `    ``set1 ``=` `set``() ` ` `  `    ``# Put all the digits of the  ` `    ``# number in the set ` `    ``while``(number > ``0``): ` `        ``digit ``=` `number ``%` `10` `        ``set1.add(digit) ` `        ``number ``=` `int``(number ``/` `10``) ` ` `  `    ``# Since a HashSet does not allow  ` `    ``# duplicates so only a single copy  ` `    ``# of '0' and '1' will be stored ` `    ``set1.discard(``0``) ` `    ``set1.discard(``1``) ` `     `  `    ``# If the original number only  ` `    ``# contained 0's and 1's then  ` `    ``# size of the set must be 0 ` `    ``if` `(``len``(set1) ``=``=` `0``): ` `        ``return` `True` ` `  `    ``return` `False` `     `  `# Driver code ` `if` `__name__ ``=``=` `'__main__'``: ` `    ``n ``=` `1000111` `    ``if``(isBinary(n) ``=``=` `1``): ` `        ``print``(``"true"``) ` `    ``else``: ` `        ``print``(``"No"``) ` ` `  `# This code is contributed by ` `# Surendra_Gangwar `

## C#

 `     `  `// C# program to check whether the given number ` `// is in binary format ` `using` `System; ` `using` `System.Collections.Generic; ` `public` `class` `GFG { ` `  `  `    ``// Function that returns true if given number ` `    ``// is in binary format  i.e. number contains ` `    ``// only 0's and/or 1's ` `    ``static` `bool` `isBinary(``int` `number) ` `    ``{ ` `        ``HashSet<``int``> ``set` `= ``new` `HashSet<``int``>(); ` `  `  `        ``// Put all the digits of the number in the set ` `        ``while` `(number > 0) { ` `            ``int` `digit = number % 10; ` `            ``set``.Add(digit); ` `            ``number /= 10; ` `        ``} ` `  `  `        ``// Since a HashSet does not allow duplicates so only ` `        ``// a single copy of '0' and '1' will be stored ` `        ``set``.Remove(0); ` `        ``set``.Remove(1); ` `  `  `        ``// If the original number only contained 0's and 1's ` `        ``// then size of the set must be 0 ` `        ``if` `(``set``.Count == 0) { ` `            ``return` `true``; ` `        ``} ` `        ``return` `false``; ` `    ``} ` `  `  `    ``// Driver code ` `    ``public` `static` `void` `Main() ` `    ``{ ` `        ``int` `n = 1000111; ` `        ``Console.WriteLine(isBinary(n)); ` `    ``} ` `} ` `//This code is contributed by Rajput-Ji `

Output:

```true
```

Method #2: Native Way

## C++

 `// CPP program to check whether the  ` `// given number is in binary format ` `#include ` `using` `namespace` `std; ` ` `  `// Function that returns true if  ` `// given number is in binary format ` `// i.e. number contains only 0's and/or 1's ` `int` `isBinary(``int` `number) ` `{ ` `    ``while` `(number > 0)  ` `    ``{ ` `        ``int` `digit = number % 10; ` ` `  `        ``// If digit is other than 0 and 1 ` `        ``if` `(digit > 1) ` `            ``return` `false``; ` `        ``number /= 10; ` `    ``} ` `    ``return` `true``; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `  ``int` `n = 1000111; ` `  ``if` `(isBinary(n) == 1) ` `    ``cout << ``"true"``; ` `  ``else` `    ``cout << ``"false"``; ` ` `  `// This code is contributed ` `// by Shivi_Aggarwal ` `} `

## Java

 `// Java program to check whether the  ` `// given number is in binary format ` ` `  `class` `GFG { ` ` `  `    ``// Function that returns true if  ` `    ``// given number is in binary format ` `    ``// i.e. number contains only 0's and/or 1's ` `    ``static` `boolean` `isBinary(``int` `number) ` `    ``{ ` `        ``while` `(number > ``0``) { ` `            ``int` `digit = number % ``10``; ` ` `  `            ``// If digit is other than 0 and 1 ` `            ``if` `(digit > ``1``) ` `                ``return` `false``; ` `            ``number /= ``10``; ` `        ``} ` `        ``return` `true``; ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `main(String a[]) ` `    ``{ ` `        ``int` `n = ``1000111``; ` `        ``System.out.println(isBinary(n)); ` `    ``} ` `} `

## Python3

 `# Python3 program to check whether the  ` `# given number is in binary format ` ` `  `# Function that returns true if  ` `# given number is in binary format ` `# i.e. number contains only 0's and/or 1's ` `def` `isBinary(number): ` ` `  `    ``while` `(number > ``0``): ` `        ``digit ``=` `number ``%` `10` ` `  `        ``# If digit is other than 0 and 1 ` `        ``if` `(digit > ``1``): ` `            ``return` `False` `        ``number ``/``/``=` `10` `     `  `    ``return` `True` ` `  `# Driver code ` `if` `__name__ ``=``=` `"__main__"``: ` ` `  `    ``n ``=` `1000111` `    ``if` `(isBinary(n) ``=``=` `1``): ` `        ``print` `(``"true"``) ` `    ``else``: ` `        ``print` `(``"false"``) ` ` `  `# This code is contributed by ita_c `

## C#

 `// C# program to check whether the  ` `// given number is in binary format ` ` `  `using` `System; ` ` `  `class` `GFG { ` ` `  `    ``// Function that returns true if  ` `    ``// given number is in binary format ` `    ``// i.e. number contains only 0's and/or 1's ` `    ``static` `bool` `isBinary(``int` `number) ` `    ``{ ` `        ``while` `(number > 0) { ` `            ``int` `digit = number % 10; ` ` `  `            ``// If digit is other than 0 and 1 ` `            ``if` `(digit > 1) ` `                ``return` `false``; ` `            ``number /= 10; ` `        ``} ` `        ``return` `true``; ` `    ``} ` ` `  `    ``// Driver code ` `    ``static` `void` `Main() ` `    ``{ ` `        ``int` `n = 1000111; ` `        ``Console.WriteLine(isBinary(n)); ` `    ``} ` `    ``// This code is contributed by Ryuga ` `} `

## PHP

 ` 0)  ` `    ``{ ` `        ``\$digit` `= ``\$number` `% 10; ` ` `  `        ``// If digit is other than 0 and 1 ` `        ``if` `(``\$digit` `> 1) ` `            ``return` `false; ` `        ``\$number` `/= 10; ` `    ``} ` `    ``return` `true; ` `} ` ` `  `// Driver code ` `\$n` `= 1000111; ` `if` `(isBinary(``\$n``) == 1) ` `    ``echo` `"true"``; ` `else` `    ``echo` `"false"``; ` ` `  `// This code is contributed ` `// by Mukul Singh `

Output:

```true
```

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