c-class command: c(alpha) & c(ALPHA): 

a b c d e f g h i j k l m n o p q r s t u v w x y z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

E

G
H
I

a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z

letter 1 is a
letter 2 is b
letter 3 is c
letter 4 is d
letter 5 is e
letter 6 is f
letter 7 is g
letter 8 is h
letter 9 is i
letter 10 is j
letter 11 is k
letter 12 is l
letter 13 is m
letter 14 is n
letter 15 is o
letter 16 is p
letter 17 is q
letter 18 is r
letter 19 is s
letter 20 is t
letter 21 is u
letter 22 is v
letter 23 is w
letter 24 is x
letter 25 is y
letter 26 is z

HINT: bonus point challenge in chapter: tokenize
DEMO.XPT
DEMO_B.XPT
DEMO_C.XPT

   1:      0.00 /        1 =       0.0010
   2:      0.00 /        1 =       0.0010
   3:      9.16 /        1 =       9.1570