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# Check whether all the bits are unset in the given range

• Last Updated : 28 Apr, 2021

Given a non-negative number n and two values l and r. The problem is to check whether all the bits are unset or not in the range l to r in the binary representation of n. The bits are numbered from right to left, i.e., the least significant bit is considered to be at first position.
Constraint: 1 <= l <= r <= number of bits in the binary representation of n.
Examples:

```Input : n = 17, l = 2, r = 4
Output : Yes
(17)10 = (10001)2
The bits in the range 2 to 4 are all unset.

Input : n = 39, l = 4, r = 6
Output : No
(39)10 = (100111)2
The bits in the range 4 to 6 are all not unset.```

Approach: Following are the steps:

1. Calculate num = ((1 << r) – 1) ^ ((1 << (l-1)) – 1). This will produce a number num having r number of bits and bits in the range l to r are the only set bits.
2. Calculate new_num = n & num.
3. If new_num == 0, return “Yes” (all bits are unset in the given range).
4. Else return “No” (all bits are not unset in the given range).

## C++

 `// C++ implementation to check whether all the bits``// are unset in the given range or not``#include ` `using` `namespace` `std;` `// function to check whether all the bits``// are unset in the given range or not``bool` `allBitsSetInTheGivenRange(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);` `    ``// new number which could only have one or more``    ``// set bits in the range l to r and nowhere else``    ``int` `new_num = n & num;` `    ``// if true, then all bits are unset``    ``// in the given range``    ``if` `(new_num == 0)``        ``return` `true``;` `    ``// else all bits are not unset``    ``// in the given range``    ``return` `false``;``}` `// Driver program to test above``int` `main()``{``    ``unsigned ``int` `n = 17;``    ``unsigned ``int` `l = 2, r = 4;``    ``if` `(allBitsSetInTheGivenRange(n, l, r))``        ``cout << ``"Yes"``;``    ``else``        ``cout << ``"No"``;``    ``return` `0;``}`

## Java

 `// Java implementation to check``// whether all the bits are``// unset in the given range or not``class` `GFG``{``    ` `// function to check whether``// all the bits are unset in``// the given range or not``static` `boolean` `allBitsSetInTheGivenRange(``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``);` `    ``// new number which could only``    ``// have one or more set bits in``    ``// the range l to r and nowhere else``    ``int` `new_num = n & num;` `    ``// if true, then all bits are``    ``// unset in the given range``    ``if` `(new_num == ``0``)``        ``return` `true``;` `    ``// else all bits are not``    ``// unset in the given range``    ``return` `false``;``}` `// Driver Code``public` `static` `void` `main(String[] args)``{``    ``int` `n = ``17``;``    ``int` `l = ``2``, r = ``4``;``    ``if` `(allBitsSetInTheGivenRange(n, l, r))``        ``System.out.println(``"Yes"``);``    ``else``        ``System.out.println(``"No"``);``}``}` `// This code is contributed``// by Smitha`

## Python3

 `# Python3 implementation to``# check whether all the bits``# are unset in the given``# range or not` `# function to check whether``# all the bits are unset in``# the given range or not``def` `allBitsSetInTheGivenRange(n, l, r):` `    ``# calculating a number 'num'``    ``# having 'r' number of bits``    ``# and bits in the range l``    ``# to r are the only set bits``    ``num ``=` `(((``1` `<< r) ``-` `1``) ^``           ``((``1` `<< (l ``-` `1``)) ``-` `1``))` `    ``# new number which could only``    ``# have one or more set bits in``    ``# the range l to r and nowhere else``    ``new_num ``=` `n & num` `    ``# if true, then all bits are``    ``# unset in the given range``    ``if` `(new_num ``=``=` `0``):``        ``return` `True` `    ``# else all bits are not``    ``# unset in the given range``    ``return` `false` `# Driver Code``n ``=` `17``l ``=` `2``r ``=` `4``if` `(allBitsSetInTheGivenRange(n, l, r)):``    ``print``(``"Yes"``)``else``:``    ``print``(``"No"``)` `# This code is contributed``# by Smitha`

## C#

 `// C# implementation to check``// whether all the bits are``// unset in the given range or not``using` `System;` `class` `GFG``{``    ` `// function to check whether``// all the bits are unset in``// the given range or not``static` `bool` `allBitsSetInTheGivenRange(``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);` `    ``// new number which could ``    ``// only have one or more``    ``// set bits in the range``    ``// l to r and nowhere else``    ``int` `new_num = n & num;` `    ``// if true, then all``    ``// bits are unset``    ``// in the given range``    ``if` `(new_num == 0)``        ``return` `true``;` `    ``// else all bits are not``    ``// unset in the given range``    ``return` `false``;``}` `// Driver Code``public` `static` `void` `Main()``{``    ``int` `n = 17;``    ``int` `l = 2, r = 4;``    ``if` `(allBitsSetInTheGivenRange(n, l, r))``        ``Console.Write(``"Yes"``);``    ``else``        ``Console.Write(``"No"``);``}``}` `// This code is contributed``// by Smitha`

## PHP

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## Javascript

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Output:

`Yes`

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