#!/bin/bash
declare -a key # declare key as array

echo "Please key in four key"

read key[0,1,2,3]



i=0

for c in "${key[@]}"

do

    lkey[$i]=${c,,}

    i=$((${i} + 1))

done # translate all alphabet to lower character,lkey



function let2num {

	for i in `echo "$1" | grep -o . ` ; do

		echo $((`printf '%d' "'$i"` -97))

	done

}

echo "What is your option"

echo "1) Encryption"

echo "2) Decryption"

echo "3) Exit"

read option;



if [ "$option"  -eq "1" ];  then

echo "You selected Encryption"

elif [ "$option" -eq "2" ];  then

echo "You selected Decrypion"

elif [ "$option" -eq "3" ];  then

echo "You selected Exit,program will exit soon"

exit 0

else

echo "Invalid input,program will terminated soon"

exit 0

fi

echo "The key is ${lkey[@]}"
echo `let2num ${lkey[@]}`