This question is about the linked list classes SLLNode and SLList discussed

in lectures last week.

$($a$)$ Consider the following specification for a program deleteLast inside

of the class SLList.

void deleteLast $()$

$//$ Postcondition: Removes the very last node from the list,

$//$ if it exists, leaving all other nodes in the list.

Given the following "before execution" diagrams, sketch the corre$-$

sponding "after execution" diagrams, i$.$e$.$ assuming the three initial

configurations for the input list, what are the corresponding config$-$

$($b$)$ Now fill in the gaps indicated by $???$ to complete the implementation

of deleteLast.

void deleteLast$()\{$

if $($head$!=$ null$)$ The list has no nodes

if $($head$.$next$==$null$)$ The list has one node

head$=???$

$\}$

else The list has at least two nodes

SLLNode temp$=???//$ search for the next but last node....

while$($temp$.$next.next!$=$null$)\{$

temp$=???$

$\}//$ Hint: what node does temp point to now?

temp.next $=???$

$\}$

$\}$

$\}$urations after executing deleteLast. Below is the code for the DeleteLast program public void delete$($Object el$)\{//$ find and remove el;

if $($head $!=$ null$)//$ if non$-$empty list;

if $($el$.$equals$($head$.$info$))//$ if head needs to be removed;

head $=$ head.next;

else $\{$

SLLNode pred $=$ head, tmp $=$ head.next;

for $($ ; tmp $!=$ null && $!($tmp$.$info.equals$($el$))$;

pred $=$ pred.next, tmp $=$ tmp$.$next$)$;

if $($tmp $!=$ null$)//$ if found

pred.next $=$ tmp$.$next;

$\}$

$\}$