I just need help with the void switchSecondAndThird(const Node * s) Thanks!

#include using namespace::std;

struct Node { int data; Node * next; Node * prev; };

void addFront(Node * & s, int value) { if ( s == NULL ) { s = new Node; s->data = value; s->next = NULL; s->prev = NULL; return; } Node * p = new Node; p->data = value; p->prev = NULL; // prev is NULL for first node s->prev = p; // old first node points backward to new first node p->next = s; // new first node points forward to old first node s = p; // s now points to new first node }

void printForward(const Node * s) { const Node * walker = s; while ( walker != NULL ) { cout << walker->data << " "; walker = walker->next; } cout << endl; }

void deleteDoubleLinkedList(Node *s) { if ( s == NULL ) return; // 0 nodes if ( s->next == NULL ) // 1 node { delete s; return; } Node * prev = s; Node * current = prev->next; while ( current != NULL ) { cout << "deleting " << prev-> data << endl; delete prev; prev = current; current = current->next; } cout << "deleting " << prev-> data << endl; delete prev; cout << "All memory returned for double linked list starting at " << s << endl; }

void deleteDoulbeLinkedListRecursive(Node * s) // write a recursive algorithm { /*if (s == nullptr) { cout << "Empty List" << endl; } if (s->next == NULL) { delete s; return; } while (s != nullptr) { cout << "Deleting " << s->data << endl; delete s; deleteDoulbeLinkedListRecursive(s->next); } s = nullptr; //delete s;*/ if (s == nullptr) { cout << "Empty List" << endl; return; } Node *temp = s; if (s->next == nullptr) { cout << "Deleting " << s->data << endl; //s->next = nullptr; delete s; deleteDoulbeLinkedListRecursive(temp->next); //s = s->next; //delete s; //deleteDoulbeLinkedListRecursive(s->next); } temp = nullptr; }

int sumOfDataInNodes(const Node * s) // student writes this function { if(s == nullptr) return 0; return s->data + sumOfDataInNodes(s->next); }

void printBackward(const Node * s) // student writes this function { if(s == nullptr) cout << "" << endl; const Node * walker = s; while (walker->next != nullptr) { walker = walker->next; } cout << walker->data << " "; while (walker->prev != nullptr) { cout << walker->prev->data << " "; walker = walker->prev; } cout << endl; delete walker; walker = nullptr; return; }

void switchSecondAndThird(const Node * s) // assume at least 3 nodes Student writes this function // MOVE POINTERS, DO NOT MOVE DATA // CONSIDER A SPECIAL CASE OF EXACTLY 3 NODES, i.e., THERE IS NO 4TH NODE POINTING BACK TO THE THIRD NODE { }

void main() { Node * start = NULL; for ( int i = 50; i >= 10; i-=10 ) { addFront(start,i); } //cout <<"Start forward is "; //printForward(start); //cout <<"Start backward is "; //printBackward(start); cout << "The sum of the data is start is " << sumOfDataInNodes(start) << endl; //switchSecondAndThird(start); cout <<"Start forward after switching is "; printForward(start); cout <<"Start backward after switching is "; printBackward(start); deleteDoulbeLinkedListRecursive(start); //printForward(start);

/*Node * special = NULL; for ( int i = 130; i >= 110; i-=10 ) { addFront(special,i); } cout <<"Special forward is "; printForward(special); cout <<"Special backward is "; printBackward(special); switchSecondAndThird(special); cout <<"Special forward after switching is "; printForward(special); cout <<"Special backward after switching is "; printBackward(special); cout << "Return memory for Start" << endl; deleteDoubleLinkedList(start); */ }