Task — Binary string

You are given an integer, $n > 0. Write a script to find all possible binary numbers of size $n.

Examples

Example 1
Input: $n = 2
Output: 00, 11, 01, 10

Example 2
Input: $n = 3
Output: 000, 001, 010, 100, 111, 110, 101, 011

Analysis

We are asked to find all the binary numbers 'of length $n'. The examples show that means 'containing n digits' and that the desired solution includes those with leading zeroes.

The numbers are simply all the integers from 0 .. 2 ^ ($n - 1), and we can loop over that range, outputting the numbers in binary format using the binary option of sprintf. It looks a little odd:

sprintf("%0${n}b", $_)

but if, say $n == 4, that amounts to

sprintf("%04b", $_)

which means 4 binary digits with leading zeroes.

Try it 

#!/usr/bin/perl

# Peter Campbell Smith - 2022-11-28
# PWC 193 task 1

use v5.28;
use utf8;
use warnings;

my (@tests, $n, $j, $string);

@tests = (2, 3, 4, 6);

# loop over tests
for $n (@tests) {
    
    # format as binary
    $string = '';
    $string .= sprintf("%0${n}b", $_) . ', ' for (0 .. 2 ** $n - 1);
    
    # show output
    say qq[\nInput:  $n\nOutput: ] . substr($string, 0, -2);
}

Output

Input:  2
Output: 00, 01, 10, 11

Input:  3
Output: 000, 001, 010, 011, 100, 101, 110, 111

Input:  4
Output: 0000, 0001, 0010, 0011, 0100, 0101, 0110, 0111, 
  1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111

Input:  6
Output: 000000, 000001, 000010, 000011, 000100, 000101,
  000110, 000111, 001000, 001001, 001010, 001011, 001100,
  001101, 001110, 001111, 010000, 010001, 010010, 010011,
  010100, 010101, 010110, 010111, 011000, 011001, 011010,
  011011, 011100, 011101, 011110, 011111, 100000, 100001, 100010, 100011, 100100, 100101, 100110, 100111, 101000, 101001, 101010, 101011, 101100, 101101, 101110, 101111,
  110000, 110001, 110010, 110011, 110100, 110101, 110110,
  110111, 111000, 111001, 111010, 111011, 111100, 111101,
  111110, 111111