AlphaNumeric String Operations

Hi

I am writing a ksh

I have a string of general format

A12B3456CD78

the string is of variable length

the string always ends with numbers (here it is 78.. it can be any number of digits may be 789 or just 7)

before these ending numbers are alphabets (here it is CD can even be C alone or CDX ..that is length can be varied)

before the CD is a string of variable length that always ends in digits here A12B3456 ....

i want to extract each of these seperately ..
ie
part one A12B3456
part two CD
part three 78

this is a bit complicated for me ... plz help me out

echo A12B3456CD78 | sed "s/\([0-9]*\)$/\\
\1/" | sed "1 s/\([a-zA-Z]*\)$/\\
\1/"

[/tmp]$ cat ./try.ksh
#! /bin/ksh

in=A12B3456CD78

f3=$(echo $in | tr '[A-Z]' ' ')
f3=${f3##* }
in=${in%$f3}
f2=$(echo $in | tr '[0-9]' ' ')
f2=${f2##* }
f1=${in%$f2}
echo "$f1"
echo "$f2"
echo "$f3"

[/tmp]$ ./try.ksh
A12B3456
CD
78
[/tmp]$ 

# !/opt/third-party/bin/zsh
                                                                                 
str="A12B3456CD78"
                                                                                 
only_num=$(echo $str | tr '[A-Za-z]' ' ' | awk '{print $NF}')
only_alpha=$(echo $str | tr '[0-9]' ' ' | awk '{print $NF}')
echo $str $only_num $only_alpha | awk '{ print (substr ($0,0,length($1) - ( length($2) + length($3) ))), "\n", $2, "\n", $3 }'
                                                                                 
exit 0