#!/bin/bash -x

# Program to take a user numerical input number and return it as a sentence.
#
#
#
read -p "Enter a number no higher than the billions range" NUM

NUMBEROFDIGITS=${#NUM}


FindNumberOfGroups() {
    if [[ `expr ${NUMBEROFDIGITS} % 3` -ne 0 ]]; then # line is good for determining if there is an odd number of digits when dividing by 3 {
		let NUMBEROFGROUPS=NUMBEROFGROUPS+1
		ISEVEN=false
	fi #}
}

####################
### END FUNCTION ###
####################

NUMBEROFGROUPS=$( expr ${NUMBEROFDIGITS} / 3 )
ISEVEN=true

FindNumberOfGroups

echo ${NUMBEROFGROUPS}


while [ ${NUMBEROFGROUPS} -gt 0 ]; do #{
	# this code is to deal with the first two digits when and if NUM is not even when divded by 3
	if [[ ${ISEVEN} == false ]]; then #{
		EVENDIGITS=$(( NUMBEROFDIGITS / 3 ))
		echo ${EVENDIGITS}
		let EVENDIGITS=EVENDIGITS*3
		echo ${EVENDIGITS}
		#echo ${NUM:EVENDIGITS}
		ODDDIGITS=${NUM:EVENDIGITS}
		echo ${ODDDIGITS}
	fi #}
	D1=${NUM:0:1}
	D2=${NUM:1:1}
    D3=${NUM:2:1}

	#echo ${NUMBEROFGROUPS:0:4}
	echo "${D1} ${D2} ${D3}"

	let NUMBEROFGROUPS--

	#echo ${NUMBEROFGROUPS:0:3}
	#echo "${D1} ${D2} ${D3}"
done #}

#echo "${D1} ${D2} ${D3}"

+ read -p 'Enter a number no higher than the billions range' NUM
Enter a number no higher than the billions range120
+ NUMBEROFDIGITS=3
++ expr 3 / 3
+ NUMBEROFGROUPS=1
+ ISEVEN=true
+ FindNumberOfGroups
++ expr 3 % 3
+ [[ 0 -ne 0 ]]
+ echo 1
1
+ '[' 1 -gt 0 ']'
+ [[ true == false ]]
+ D1=1
+ D2=2
+ D3=0
+ echo '1 2 0'
1 2 0
+ let NUMBEROFGROUPS--
+ '[' 0 -gt 0 ']'