# Unset bits in the given range

Given a non-negative number n and two values l and r. The problem is to unset the bits in the range l to r in the binary representation of n, i.e, to unset bits from the rightmost lth bit to the rightmost rth bit.

Constraint: 1 <= l <= r <= number of bits in the binary representation of n.

Examples:

```Input : n = 42, l = 2, r = 5
Output : 32
(42)10 = (101010)2
(32)10 = (100000)2
The bits in the range 2 to 5 in the binary
representation of 42 have been unset.

Input : n = 63, l = 1, r = 4
Output : 48
```

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

Approach: Following are the steps:

1. Calculate num = (1 << (sizeof(int) * 8 – 1)) – 1. This will produce the highest positive integer num. All the bits in num will be set.
2. Toggle bits in the range l to r in num. Refer this post.
3. Now, perform n = n & num. This will unset the bits in the range l to r in n.
4. Return n.

Note: The sizeof(int) has been used as input is of int data type. For large inputs you can use long int or long long int datatypes in place of int.

## C/C++

```// C++ implementation to unset bits in the given range
#include <bits/stdc++.h>

using namespace std;

// function to toggle bits in the given range
unsigned int toggleBitsFromLToR(unsigned int n,
unsigned int l,
unsigned int r)
{
// calculating a number 'num' having 'r' number of bits
// and bits in the range l to r are the only set bits
int num = ((1 << r) - 1) ^ ((1 << (l - 1)) - 1);

// toggle the bits in the range l to r in 'n'
// and return the number
return (n ^ num);
}

// function to unset bits in the given range
unsigned int unsetBitsInGivenRange(unsigned int n,
unsigned int l, unsigned int r)
{
// 'num' is the highest positive integer number
// all the bits of 'num' are set
unsigned int num = (1 << (sizeof(int) * 8 - 1)) - 1;

// toggle the bits in the range l to r in 'num'
num = toggleBitsFromLToR(num, l, r);

// unset the bits in the range l to r in 'n'
// and return the number
return (n & num);
}

// Driver program to test above
int main()
{
unsigned int n = 42;
unsigned int l = 2, r = 5;
cout << unsetBitsInGivenRange(n, l, r);
return 0;
}
```

## Java

```// Java implementation to unset bits in the given range
import java.io.*;

class GFG
{
// Function to toggle bits in the given range
static int toggleBitsFromLToR(int n, int l, int r)
{
// calculating a number 'num' having 'r' number of bits
// and bits in the range l to r are the only set bits
int num = ((1 << r) - 1) ^ ((1 << (l - 1)) - 1);

// toggle the bits in the range l to r in 'n'
// and return the number
return (n ^ num);
}

// Function to unset bits in the given range
static int unsetBitsInGivenRange(int n, int l, int r)
{
// 'num' is the highest positive integer number
// all the bits of 'num' are set
int num = (1 << (4 * 8 - 1)) - 1;

// toggle the bits in the range l to r in 'num'
num = toggleBitsFromLToR(num, l, r);

// unset the bits in the range l to r in 'n'
// and return the number
return (n & num);
}

// driver program
public static void main (String[] args)
{
int n = 42;
int l = 2, r = 5;
System.out.println(unsetBitsInGivenRange(n, l, r));
}
}

// Contributed by Pramod Kumar
```

Output:

```32
```

This article is contributed by Ayush Jauhari. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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