# Find, Set, Clear, Toggle and Modify bits in C

• Difficulty Level : Medium
• Last Updated : 11 Dec, 2020

Given a positive integer N, the task is to perform the following sequence of operations on the binary representation of N in C.

Examples:

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Input:N = 5, K = 1, P = 0
Output:
K(= 1)th bit of 5 is 1.
Setting the K(= 1)th bit modifies N to 5
Clearing the K(= 1)th bit modifies N to 4.
Toggling the K(= 1)th bit modifies N to 4.
Replacing the K(= 1)th bit with P(= 0) modifies N to 4

Input: N = 10, K = 2, P = 1
Output:
Kth(= 2) bit of 5 is 1.
Setting the K(= 2)th bit modifies N to 10.
Clearing the K(= 2)th bit modifies N to 8.
Toggling the K(= 2)th bit modifies N to 8.
Replacing the K(= 2)th bit with P(= 1) modifies N to 10.

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

Approach: Follow the steps below to find, set, clear, toggle and modify the Kth bit in the binary representation of N.

Finding a bit:

` (N >> K) & 1`

Setting a bit:

` N = N | (1 << K)`

Clearing a bit:

` N = N & ~(1 << K)`

Toggle a bit:

` N = N ^ (1 << K)`

Modify a bit:

` N = N | (P << K)`

Below is the implementation of the above approach:

## C

 `// C program to implement``// the above approach`` ` `#include `` ` `// Function to set the kth bit of n``int` `setBit(``int` `n, ``int` `k)``{``    ``return` `(n | (1 << (k - 1)));``}`` ` `// Function to clear the kth bit of n``int` `clearBit(``int` `n, ``int` `k)``{``    ``return` `(n & (~(1 << (k - 1))));``}`` ` `// Function to toggle the kth bit of n``int` `toggleBit(``int` `n, ``int` `k)``{``    ``return` `(n ^ (1 << (k - 1)));``}`` ` `// Function to modify k-th bit with p``int` `modifyBit(``int` `n, ``int` `k, ``int` `p)``{``    ``return` `(n | (p << k));``}`` ` `// Function to find the kth bit of n``int` `findBit(``int` `n, ``int` `k)``{``    ``return` `((n >> k) & 1);``}`` ` `// Utility function to perform``// the specified Bit Operations``void` `bitOperations(``int` `n, ``int` `k,``                   ``int` `p)``{`` ` `    ``printf``(``"K(= %d)-th bit of %d is %d\n"``,``           ``k, n, findBit(n, k));`` ` `    ``printf``(``"Setting K(= %d)th bit modifies N to %d\n"``,``           ``k, setBit(n, k));`` ` `    ``printf``(``"Clearing K(= %d)th bit modifies N to %d\n"``,``           ``k, clearBit(n, k));`` ` `    ``printf``(``"Toggling K(= %d)th bit modifies N to %d\n"``,``           ``k, toggleBit(n, k));`` ` `    ``printf``(``"Replacing the K(= %d)th bit"``, k);``    ``printf``(``" with P(= %d) modifies N to 10\n"``,``           ``modifyBit(n, k, p));``}`` ` `// Driver Code``int` `main()``{``    ``int` `n = 5, k = 1, p = 1;``    ``bitOperations(n, k, p);`` ` `    ``return` `0;``}`
Output:
```K(= 1)-th bit of 5 is 0
Setting K(= 1)th bit modifies N to 5
Clearing K(= 1)th bit modifies N to 4
Toggling K(= 1)th bit modifies N to 4
Replacing the K(= 1)th bit with P(= 7) modifies N to 10
```

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

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