> For the complete documentation index, see [llms.txt](https://gl01.gitbook.io/gfg-editorials/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gl01.gitbook.io/gfg-editorials/2023/10-2023-oct-28/29-check-whether-k-th-bit-is-set-or-not.md).

# 29. Check whether K-th bit is set or not

The problem can be found at the following link: [Question Link](https://practice.geeksforgeeks.org/problems/check-whether-k-th-bit-is-set-or-not-1587115620/1)

![](https://badgen.net/badge/Level/Easy/green)

## My Approach

To check whether the K-th bit is set in an integer `n`, I use a bit manipulation technique.

* I create a mask with the K-th bit set to 1 by left-shifting 1 by K positions.
* Then, I perform a bitwise AND operation between `n` and the mask. If the result is greater than 0, it means the K-th bit is set; otherwise, it's not set.

## Time and Auxiliary Space Complexity

* **Time Complexity**: `O(1)` - The time complexity is constant because the number of operations is not dependent on the size of the input.
* **Auxiliary Space Complexity**: `O(1)` - The auxiliary space complexity is constant because we use a fixed amount of memory for the mask and the result.

## Code (C++)

```cpp
class Solution {
public:
    bool checkKthBit(int n, int k) {
        int mask = 1 << k; 
        return (n & mask) > 0;
    }
};
```

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