# Check whether K-th bit is set or not

• Difficulty Level : Easy
• Last Updated : 10 Aug, 2022

Given a number n, check if the Kth bit of n is set or not.

Examples: ```Input : n = 5, k = 1
Output : SET
5 is represented as 101 in binary and has its first bit set.

Input : n = 2, k = 3
Output : NOT SET
2 is represented as 10 in binary, all higher i.e. beyond MSB, bits are NOT SET.```

Method 1 (Using Left Shift Operator)
Below are simple steps to find the value of Kth bit:

```1) Left shift given number 1 by k-1 to create a number that has only set bit as k-th bit.
temp = 1 << (k-1)
2) If bitwise AND of n and temp is non-zero, then result is SET else result is NOT SET.```

Example:

``` n = 75 and k = 4
temp = 1 << (k-1) = 1 << 3 = 8
Binary Representation of temp = 0..00001000
Binary Representation of n = 0..01001011
Since bitwise AND of n and temp is non-zero, result is SET.```

## C++

 `// CPP program to check if k-th bit``// of a given number is set or not``#include ``using` `namespace` `std;` `void` `isKthBitSet(``int` `n, ``int` `k)``{``    ``if` `(n & (1 << (k - 1)))``        ``cout << ``"SET"``;``    ``else``        ``cout << ``"NOT SET"``;``}` `// Driver code``int` `main()``{``    ``int` `n = 5, k = 1;``    ``isKthBitSet(n, k);``    ``return` `0;``}`

## C

 `// C program to check if k-th bit``// of a given number is set or not``#include ` `void` `isKthBitSet(``int` `n, ``int` `k)``{``    ``if` `(n & (1 << (k - 1)))``        ``printf``(``"SET"``);``    ``else``        ``printf``(``"NOT SET"``);``}` `// Driver code``int` `main()``{``    ``int` `n = 5, k = 1;``    ``isKthBitSet(n, k);``    ``return` `0;``}` `// this code is contributed by devendrasaluke`

## Java

 `// Java program to check if k-th bit``// of a given number is set or not` `class` `Number {``    ``public` `static` `void` `isKthBitSet(``int` `n,``                                   ``int` `k)``    ``{``        ``if` `((n & (``1` `<< (k - ``1``))) > ``0``)``            ``System.out.print(``"SET"``);``        ``else``            ``System.out.print(``"NOT SET"``);``    ``}` `    ``// driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``int` `n = ``5``, k = ``1``;``        ``isKthBitSet(n, k);``    ``}``}` `// This code is contributed by rishabh_jain`

## Python3

 `# Python3 code to check if k-th bit``# of a given number is set or not` `def` `isKthBitSet(n, k):``    ``if` `n & (``1` `<< (k ``-` `1``)):``        ``print``( ``"SET"``)``    ``else``:``        ``print``(``"NOT SET"``)` `# Driver code``n ``=` `5``k ``=` `1``isKthBitSet(n, k)` `# This code is contributed by "Sharad_Bhardwaj".`

## C#

 `// C# program to check if k-th bit``// of a given number is set or not.``using` `System;` `class` `GFG {` `    ``public` `static` `void` `isKthBitSet(``int` `n,``                                   ``int` `k)``    ``{``        ``if` `((n & (1 << (k - 1))) > 0)``            ``Console.Write(``"SET"``);``        ``else``            ``Console.Write(``"NOT SET"``);``    ``}` `    ``// Driver code``    ``public` `static` `void` `Main()``    ``{``        ``int` `n = 5, k = 1;` `        ``isKthBitSet(n, k);``    ``}``}` `// This code is contributed by nitin mittal.`

## PHP

 ``

## Javascript

 ``

Output:

`SET`

Time Complexity : O(1)

Auxiliary Space: O(1)

Method 2 (Using Right Shift Operator)
If we right shift n by k-1, we get the last bit as 1 if Kth bit is set else 0.

## C++

 `// CPP program to check if k-th bit``// of a given number is set or not using``// right shift operator.``#include ``using` `namespace` `std;` `void` `isKthBitSet(``int` `n, ``int` `k)``{``    ``if` `((n >> (k - 1)) & 1)``        ``cout << ``"SET"``;``    ``else``        ``cout << ``"NOT SET"``;``}` `// Driver code``int` `main()``{``    ``int` `n = 5, k = 1;``    ``isKthBitSet(n, k);``    ``return` `0;``}`

## C

 `// C program to check if k-th bit``// of a given number is set or not using``// right shift operator.``#include ` `void` `isKthBitSet(``int` `n, ``int` `k)``{``    ``if` `((n >> (k - 1)) & 1)``        ``printf``(``"SET"``);``    ``else``        ``printf``(``"NOT SET"``);``}` `// Driver code``int` `main()``{``    ``int` `n = 5, k = 1;``    ``isKthBitSet(n, k);``    ``return` `0;``}``// this code is contributed by devendrasolunke`

## Java

 `// Java program to check if``// k-th bit of a given number``// is set or not using right``// shift operator.``import` `java.io.*;` `class` `GFG``{``static` `void` `isKthBitSet(``int` `n,``                        ``int` `k)``{``    ``if` `(((n >> (k - ``1``)) &``               ``1``) > ``0``)``        ``System.out.println(``"SET"``);``    ``else``        ``System.out.println(``"NOT SET"``);``}` `// Driver code``public` `static` `void` `main (String[] args)``{``    ``int` `n = ``5``, k = ``1``;``    ``isKthBitSet(n, k);``}``}` `// This code is contributed``// by ajit`

## Python3

 `# PHP program to check if k-th bit of``# a given number is set or not using``# right shift operator.` `def` `isKthBitSet(n, k):``    ``if` `((n >> (k ``-` `1``)) ``and` `1``):``        ``print``(``"SET"``)``    ``else``:``        ``print``(``"NOT SET"``)` `# Driver code``n, k ``=` `5``, ``1``isKthBitSet(n, k)` `# This code contributed by``# PrinciRaj1992`

## C#

 `// C# program to check if``// k-th bit of a given number``// is set or not using right``// shift operator``using` `System;` `class` `GFG``{``static` `void` `isKthBitSet(``int` `n,``                        ``int` `k)``{``    ``if` `(((n >> (k - 1)) &``              ``1) > 0)``        ``Console.WriteLine(``"SET"``);``    ``else``        ``Console.WriteLine(``"NOT SET"``);``}` `// Driver code``static` `public` `void` `Main ()``{``    ``int` `n = 5, k = 1;``    ``isKthBitSet(n, k);``}``}` `// This code is contributed``// by ajit`

## PHP

 `> (``\$k` `- 1)) & 1)``        ``echo` `"SET"``;``    ``else``        ``echo` `"NOT SET"``;``}` `// Driver code``\$n` `= 5; ``\$k` `= 1;``isKthBitSet(``\$n``, ``\$k``);` `// This code is contributed``// by akt_mit``?>`

## Javascript

 ``

Output:

`SET`

Time Complexity : O(1)

Auxiliary Space: O(1), since no extra space has been taken.

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