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# Check whether K-th bit is set or not

• Difficulty Level : Easy
• Last Updated : 28 Nov, 2022

Given a number N and a bit number K, check if the Kth bit of N is set or not. A bit is called set if it is 1.
Note: Indexing starts with 0 from LSB (least significant bit) side in the binary representation of the number.

Examples:

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

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

## Check whether the K-th bit is set or not Using Left Shift Operator:

To solve the problem follow the below idea:

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

Below is the implementation of the above approach:

## 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))` `        ``cout << ``"SET"``;` `    ``else` `        ``cout << ``"NOT SET"``;` `}`   `// Driver code` `int` `main()` `{` `    ``int` `n = 5, k = 1;`   `    ``// Function call` `    ``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))` `        ``printf``(``"SET"``);` `    ``else` `        ``printf``(``"NOT SET"``);` `}`   `// Driver code` `int` `main()` `{` `    ``int` `n = 5, k = 1;`   `    ``// Function call` `    ``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` `<

## 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):` `        ``print``(``"SET"``)` `    ``else``:` `        ``print``(``"NOT SET"``)`     `# Driver code` `if` `__name__ ``=``=` `"__main__"``:` `    ``n ``=` `5` `    ``k ``=` `1`   `    ``# Function call` `    ``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)) > 0)` `            ``Console.Write(``"SET"``);` `        ``else` `            ``Console.Write(``"NOT SET"``);` `    ``}`   `    ``// Driver code` `    ``public` `static` `void` `Main()` `    ``{` `        ``int` `n = 5, k = 1;`   `        ``// Function call` `        ``isKthBitSet(n, k);` `    ``}` `}`   `// This code is contributed by nitin mittal.`

## PHP

 ``

## Javascript

 ``

Output

`NOT SET`

Time Complexity: O(1)
Auxiliary Space: O(1)

## Check whether the K-th bit is set or not Using Right Shift Operator:

To solve the problem follow the below idea:

If we right shift n by k, we get the last bit as 1 if the Kth bit is set else 0

Below is the implementation of the above approach:

## 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)` `        ``cout << ``"SET"``;` `    ``else` `        ``cout << ``"NOT SET"``;` `}`   `// Driver code` `int` `main()` `{` `    ``int` `n = 5, k = 1;`   `    ``// Function call` `    ``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)` `        ``printf``(``"SET"``);` `    ``else` `        ``printf``(``"NOT SET"``);` `}`   `// Driver code` `int` `main()` `{` `    ``int` `n = 5, k = 1;`   `    ``// Function call` `    ``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``) > ``0``)` `            ``System.out.println(``"SET"``);` `        ``else` `            ``System.out.println(``"NOT SET"``);` `    ``}`   `    ``// Driver code` `    ``public` `static` `void` `main(String[] args)` `    ``{` `        ``int` `n = ``5``, k = ``1``;`   `        ``// Function call` `        ``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) ``and` `1``):` `        ``print``(``"SET"``)` `    ``else``:` `        ``print``(``"NOT SET"``)`     `# Driver code` `if` `__name__ ``=``=` `"__main__"``:` `    ``n, k ``=` `5``, ``1`   `    ``# Function call` `    ``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) > 0)` `            ``Console.WriteLine(``"SET"``);` `        ``else` `            ``Console.WriteLine(``"NOT SET"``);` `    ``}`   `    ``// Driver code` `    ``static` `public` `void` `Main()` `    ``{` `        ``int` `n = 5, k = 1;`   `        ``// Function call` `        ``isKthBitSet(n, k);` `    ``}` `}`   `// This code is contributed` `// by ajit`

## PHP

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

## Javascript

 ``

Output

`NOT SET`

Time Complexity: O(1)
Auxiliary Space: O(1)

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