Write a C program to input any number from user and clear the n^{th} bit of the given number using bitwise operator. How to clear n^{th} bit of a given number using bitwise operator in C programming. How to unset (0) the value of n^{th} bit of a given number in C.

**Example**

**Input**

Input number: 13 Input nth bit to clear: 0

**Output**

Number after clearing nth bit: 12 (in decimal)

Also read –

## Required knowledge

Bitwise operators, Data types, Variables and Expressions, Basic input/output

## Logic to clear nth bit of a number

To clear n^{th} bit of a number we will use combination of bitwise left shift `<<`

, bitwise complement `~`

and bitwise AND `&`

operator.

Below is the step by step descriptive logic to clear nth bit of a number.

- Input number and nth bit position to clear from user. Store it in some variable say
`num`and`n`. - Left shift 1,
`n`times i.e.`1 << n`

. - Perform bitwise complement with the above result. So that the n
^{th}bit becomes unset and rest of bit becomes set i.e.`~ (1 << n)`

. - Finally, perform bitwise AND operation with the above result and
`num`. The above three steps together can be written as`num & (~ (1 << n));`

Let us take an example to understand this.

## Program to clear nth bit of a number

```
/**
* C program to clear the nth bit of a number
*/
#include <stdio.h>
int main()
{
int num, n, newNum;
/* Input number from user */
printf("Enter any number: ");
scanf("%d", &num);
/* Input bit number you want to clear */
printf("Enter nth bit to clear (0-31): ");
scanf("%d", &n);
/*
* Left shifts 1 to n times
* Perform complement of above
* finally perform bitwise AND with num and result of above
*/
newNum = num & (~(1 << n));
printf("Bit cleared successfully.\n\n");
printf("Number before clearing %d bit: %d (in decimal)\n", n, num);
printf("Number after clearing %d bit: %d (in decimal)\n", n, newNum);
return 0;
}
```

Output

Enter any number: 13 Enter nth bit to clear (0-31): 0 Bit cleared successfully. Number before clearing 0 bit: 13 (in decimal) Number after clearing 0 bit: 12 (in decimal)

Happy coding 😉

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