@cassidoo's interview question from August 28, 2023

countAndSay.sh

#!/usr/bin/env bash
set -eu -o pipefail

# Define function to convert a number to English words
# this function is lifted from my countSelfChars solution from April 2, 2023:
#  https://gist.github.com/smartwatermelon/ab9b5886128e9120b1ad3deebb2f320f
function num_to_words {
  local ones=( '' one two three four five six seven eight nine )
  local tens=( '' '' twenty thirty forty fifty sixty seventy eighty ninety )
  local specials=( ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen )
  local num=$1

  # Handle numbers greater than or equal to 1000
  if [[ $num -ge 1000 ]]; then
    local thousands=$(( $num / 1000 ))
    num=$(( $num % 1000 ))
    echo -n "$(num_to_words $thousands) thousand "
  fi

  # Handle numbers between 100 and 999
  if [[ $num -ge 100 ]]; then
    local hundreds=$(( $num / 100 ))
    num=$(( $num % 100 ))
    echo -n "${ones[$hundreds]} hundred "
    if [[ $num -gt 0 ]]; then
      echo -n "and "
    fi
  fi

  # Handle numbers between 20 and 99
  if [[ $num -ge 20 ]]; then
    local tens_place=$(( $num / 10 ))
    num=$(( $num % 10 ))
    echo -n "${tens[$tens_place]} "
  fi

  # Handle numbers between 10 and 19
  if [[ $num -ge 10 && $num -lt 20 ]]; then
    local specials_place=$(( $num % 10 ))
    echo -n "${specials[$specials_place]} "
    num=0
  fi

  # Handle numbers between 0 and 9
  if [[ $num -lt 10 ]]; then
    echo -n "${ones[$num]} "
  fi
}
export -f num_to_words

function do_each() {
	AR=($@)
	AS="" S=""
	if [ ${AR[0]} -ne 1 ]; then AS="'s" S="s"; fi
	echo "$( num_to_words ${AR[0]}) ${AR[1]}$S"
	if $( command -v say ); then say "${@}$AS"; fi
}
export -f do_each

# check input
ARGC="$#" 
if [[ "$ARGC" -ne 1 ]]; then
	echo "Please enter an integer number, e.g. 123"
	exit 1
fi
STR="$1"
re='^[0-9]+$'
if ! [[ $STR =~ $re ]] ; then
   echo "error: Not a number" >&2; exit 1
fi

# iterate through input
grep -o . <<< "$STR" | sort | uniq -c | xargs -I J bash -c "do_each J"

MONTASIO:cassidoo andrewrich$ ./countAndSay.sh 112222555
two  1s
four  2s
three  5s
MONTASIO:cassidoo andrewrich$ ./countAndSay.sh 3333333333
ten   3s