In c$++$

$12\mathrm{.}73$ Doubly Linked List

Modify the given code to:

Declare member function: DeleteNode.

Implement a member function named DeleteNode that deletes the node only if currObj is not nullptr; otherwise, print "Invalid Input".

Modify the member function DeleteNode to make the objects point properly.

#include

#include

using namespace std;

class IntNode $\{$

public:

IntNode$($int dataInit $=0,$ IntNode$*$ nextLoc $=$ nullptr$)$;

void InsertAfter$($IntNode$*$ nodeLoc$)$;

IntNode$*$ GetNext$()$;

IntNode$*$ GetPrev$()$;

int GetDataVal$()$;

void PrintNodeData$()$;

void PrintList$()$; $///$ Print the entire list.

IntNode$*$ FindNode$($int x$)$;

$///$ void DeleteNode$()$; $//$ ADD THIS

private:

int dataVal;

IntNode$*$ nextNodePtr;

IntNode$*$ prevNodePtr; $//$ Now Doubly$-$Linked

$\}$;

$//$ Constructor definition

IntNode::IntNode$($int dataInit, IntNode$*$ nextLoc$)\{$

$//$ Initialize data value

this$->$dataVal $=$ dataInit;

$//$ Set next pointer

this$->$nextNodePtr $=$ nextLoc;

$//$ Update previous pointer if nextLoc is not nullptr

if $($nextLoc$)\{$

nextLoc$->$prevNodePtr $=$ this;

$\}$

$//$ Circularly link the last node to the head

else $\{$

this$->$nextNodePtr $=$ this;

this$->$prevNodePtr $=$ this;

$\}$

$\}$

$/*$ Insert node after this node.

$*$ Before: this $--$ next

$*$ After: this $--$ node $--$ next

$*/$

$//$ Inserts a node after this node

void IntNode::InsertAfter$($IntNode$*$ nodeLoc$)\{$

$//$ Store next node

IntNode$*$ tmpNext $=$ this$->$nextNodePtr;

$//$ Update pointers to insert node

this$->$nextNodePtr $=$ nodeLoc;

nodeLoc$->$prevNodePtr $=$ this;

nodeLoc$->$nextNodePtr $=$ tmpNext;

$\}$

$//$ Prints the data value of the node

void IntNode::PrintNodeData$()\{$

cout $<<$ this$->$dataVal $<<$ endl;

$\}$

$//$ Prints the entire linked list

void IntNode::PrintList$()\{$

IntNode$*$ currObj $=$ this$->$GetNext$()$; $//$ Print the list

$//$ Traverse and print the list until reaching the head

while $($currObj $!=$ this$)\{$

currObj$->$PrintNodeData$()$;

currObj $=$ currObj$->$GetNext$()$;

$\}$

$\}$

$//$ Finds a node with given data value

IntNode$*$ IntNode::FindNode$($int x$)\{$

IntNode$*$ currObj $=$ this$->$GetNext$()$; $//$ Print the list

$//$ Traverse the list until finding a node with the target value or reaching the head

while $($currObj $!=$ this$)\{$

if $($currObj$->$GetDataVal$()==$x$)\{$

return currObj;

$\}$

currObj $=$ currObj$->$GetNext$()$;

$\}$

return nullptr;

$\}$

$//$ Grab location pointed by nextNodePtr

IntNode$*$ IntNode::GetNext$()\{$

return this$->$nextNodePtr;

$\}$

$//$ Grab location pointed by prevNodePtr

IntNode$*$ IntNode::GetPrev$()\{$

return this$->$prevNodePtr;

$\}$

$//$ Returns the dataVal

int IntNode::GetDataVal$()\{$

return this$->$dataVal;

$\}$

$/*$

void IntNode::DeleteNode$()\{$

IntNode$*$ deleteNode;

deleteNode $=$ this;

$/////1.$ Make the deleteNode previous IntNode point to the IntNode following the deleteNode

$/////2.$ Make the deleteNode next IntNode point to the IntNode before the deleteNode

delete deleteNode; $//$ Now free up the memory

$\}$

$*/$

int main$()\{$

IntNode$*$ headObj $=$ nullptr; $//$ Create IntNode pointers

IntNode$*$ currObj $=$ nullptr;

IntNode$*$ lastObj $=$ nullptr;

int i$,$ x;

headObj $=$ new IntNode$(-1)$; $//$ Front of nodes list

lastObj $=$ headObj;

for $($i $=0$; i $<10$; $++$i$)\{//$

cin $>>$ x;

currObj $=$ new IntNode$($x$)$;

lastObj$->$InsertAfter$($currObj$)$; $//$ Append curr

lastObj $=$ currObj; $//$ Curr is the new last item

$\}$

headObj$->$PrintList$()$; $//$ Print the list

cin $>>$ x; $//$ Value to Delete

currObj $=$ headObj$->$FindNode$($x$)$;

$///$ Add code to delete a node if currObj is not a nullptr else print "Invalid input"

headObj$->$PrintList$()$;

return $0$;

$\}$

In c$++$