• Haskell

x :: Integer
x = sum [bit i | i <- [1..n], wannaset i]

• C++

std::bitset<n> x;

• C++

std::vector<bool> x(n, 0);

• C#

new BitArray(n);

• D

BitArray x;
x.length = n;

• Dart

final x = FixedBitArray(n);

• Go

var x *big.Int = new(big.Int)

• Go

x := make([]uint64, (n+63)/64)

• Go

x := make([]bool, n)

• JS

let x = new Buffer (Math.ceil (n / 8))

• Java

BitSet x = new BitSet(n);

• Lisp

(let ((x (make-array n :element-type 'bit))))

• PHP

$x = new BitSet($n);

• Pascal

procedure Task;
var
  x: Set Of Byte;
begin
  x:= [2,4,8,16,32,64,256];  
end;

• Pascal

procedure task;
var 
  x: TBits;
  n: integer;
begin 
  n := $FFF;
  x := TBits.Create(n);
end;

• Perl

vec($x, $n, 1) = 0;

• Python

x = bytearray(int(math.ceil(n / 8.0)))

• Python

class BitSet:
    def __init__(self, n):
        self.a = [False] * n
    def __getitem__(self, i):
        return self.a[i]
    def __setitem__(self, k, v):
        self.a[k] = v
    def __str__(self):
        s = ('01'[x] for x in self.a)
        return ''.join(s)
x = BitSet(n)

• Ruby

x = 0

• Rust

let mut x = vec![false; n];