CDL appends
a b c 
count = 3
Test CDL_PREPEND_ELEM d with elt NULL
a b c d 
Test CDL_PREPEND_ELEM e before item b
a e b c d 
Test CDL_APPEND_ELEM f with elt NULL
f a e b c d 
Test CDL_APPEND_ELEM g after item b
f a e b g c d 
count = 7
advancing head pointer
a e b g c d f 
a e b g c d f a e b g c d f a e b g c d 
a f d c g b e a f d 
deleting (b)
a e g c d f 
deleting (a)
e g c d f 
deleting (c)
e g d f 
deleting (g)
e d f 
deleting (e)
d f 
deleting (d)
f deleting (f)

DL appends
a b c 
count = 3
Test DL_PREPEND_ELEM d with elt NULL
a b c d 
Test DL_PREPEND_ELEM e before item b
a e b c d 
Test DL_APPEND_ELEM f with elt NULL
f a e b c d 
Test DL_APPEND_ELEM g after item b
f a e b g c d 
count = 7
deleting (b)
f a e g c d 
deleting (a)
f e g c d 
deleting (c)
f e g d 
deleting (g)
f e d 
deleting (e)
f d 
deleting (d)
f deleting (f)

LL appends
a b c 
count = 3
Test LL_PREPEND_ELEM d with elt NULL
a b c d 
Test LL_PREPEND_ELEM e before item b
a e b c d 
Test LL_APPEND_ELEM f with elt NULL
f a e b c d 
Test LL_APPEND_ELEM g after item b
f a e b g c d 
count = 7
deleting (b)
f a e g c d 
deleting (a)
f e g c d 
deleting (c)
f e g d 
deleting (g)
f e d 
deleting (e)
f d 
deleting (d)
f deleting (f)