A project

Write a program that reads in a phrase and encodes it with a reflection cipher.

Consider the alphabet

                     1                       2
 0 1 2 3 4 5 6 7 8 9 0 1 2     3 4 5 6 7 8 9 0 1 2 3 4 5
 -------------------------------------------------------
 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
 z y x w v u t s r q p o n  |  m l k j i h g f e d c b a

Notice that the alphabet is split in the middle between letters 12 (m) and letter 13 (n).
We could build a code that reflects letters about this point
Letter Encodes to

a z

b y

l o

m n

y b

z a

Decodes To Letter
To encode a letter below n
- Find the distance from 'a'
- Subtract that from 'z'
To encode a letter above m
- Find the distance from m
- Subtract that from 'n'

Letter	Encodes to
a	z
b	y
l	o
m	n
y	b
z	a
Decodes To	Letter

The following might be useful

string length or size (page 119)
Accessing characters in a string (page 123)
Converting letters to lower/upper case (page 124)

General plan

Main

read in a phrase
while the phrase is valid
    Encode the phrase
    Print the results.
    read in a phrase

EncodePhrase

For each letter in the phrase
    add the encoding of the letter to the code phrase
return the code phrase.

EncodeLetter

If the letter is an alphabetic letter
    if the letter is upper case
        convert the letter to lower case
    Reflect the letter
    If the original letter was upper case
        change the reflected letter to upper case.
    return the reflected letter
else
    return the original letter

ReflectLetter

if the letter is m or lower
    subtract the letter's position relative to a from z
else
    subtract the letter's position relative to m from n
return the results.

A link to rcipher.cpp, my implementation.