Question

Your task is to complete the following function/functions: 1. Given a position in the linked list, delete the node at that position.(Silver problem - Mandatory ) 2. Print the sum of all negative elements in the linked list.(Gold problem) If you want, you can refer to the the previous recitation manual (which was on Linked Lists) to implement node deletion.

#include <iostream>

using namespace std;

//----------- Define Node ---------------------------------------------------
struct Node{
int key;
Node *next;
};

//----------- Define Linked List ---------------------------------------------------
class LinkedList
{
private:
Node *head;

public:
LinkedList(){
   head = NULL;
}
void insert_begin(int newKey);
void insert_end(int newKey);
int negativeSum();
bool deleteAtIndex(int index);
   bool deleteAtHead();
void printList();
};

void LinkedList::insert_begin(int newKey){
//1. ALLOCATE NODE
Node* newNode = new Node;

//2. PUT IN THE DATA
newNode->key = newKey;

//3. Make next of newNode as head
newNode->next = head;

//4. Change the head to newNode
head = newNode;
}

void LinkedList::insert_end(int newKey){
//1. ALLOCATE NODE
Node* newNode = new Node;

//2. PUT IN THE DATA
newNode->key = newKey;

//3. Make next of newNode as NULL
newNode->next = NULL;

//4. Check if head is not Null
if(head == NULL){
head = newNode;
return;
}

//4. Traverse the LinkedList till end
Node* temp = head;

while(temp->next != NULL){
temp = temp->next;
}
temp->next = newNode;
return;
}

//TODO
int LinkedList::negativeSum(){
if(head == NULL)
return 0;

int total = 0;
int count = 0;

// TODO Complete this function

cout<<"There is(are) "<<count<<" negative number(s) in the List"<<endl;
return total;

}

// Use deleteAtHead to delete the first item in the list
bool LinkedList::deleteAtHead()
{
   bool isDeleted = false;

if(head == NULL){
cout<< "List is already empty"<<endl;
return isDeleted;
}

Node *temp = head;
   head = temp->next;
   delete temp;
isDeleted = true;

   return isDeleted;
}

//TODO
bool LinkedList::deleteAtIndex(int n)
{
bool isDeleted = false;

if(head == NULL){
cout<< "List is already empty"<<endl;
return isDeleted;
}

   Node *pres = head;
   Node *prev = NULL;

//TODO Complete this function
//isDeleted = true;

   return isDeleted;
}

void LinkedList::printList(){
Node* temp = head;

while(temp->next != NULL){
cout<< temp->key <<" -> ";
temp = temp->next;
}

cout<<temp->key<<endl;
}

int main()
{
   LinkedList li;
   cout<<"Adding nodes to List:"<<endl;
   // 2
   li.insert_begin(2);
   li.printList();
   // -1->2
   li.insert_begin(-1);
   li.printList();
   // -1->2->-7
   li.insert_end(-7);
   li.printList();
// -1->2->-7->10
   li.insert_end(10);
   li.printList();
   // -1->2->-7->10->3
   li.insert_end(3);
   li.printList();
   cout<<endl;

   cout<<"Running delete function."<<endl;

   /*******************************
   Silver Problem - Implement the deleteAtIndex function
   ********************************/

   cout<<"Deleting node at index:"<<endl;
   if(!li.deleteAtIndex(3))
   {
       cout<<"Delete failed!"<<endl;
   }
   li.printList();
   cout<<endl;

if(!li.deleteAtHead())
   {
       cout<<"Delete failed!"<<endl;
   }
   li.printList();
   cout<<endl;

cout<<"Get the sum of negatives"<<endl;

   /*******************************
   Gold Problem - Implement the negativeSum function
   ********************************/
int negsum;
negsum = li.negativeSum();
cout<<"Sum of all the negative elements is "<<negsum<<endl;

}

Answer 1

#include <iostream>

using namespace std;

//----------- Define Node ---------------------------------------------------

struct Node{

int key;

Node *next;

};

//----------- Define Linked List ---------------------------------------------------

class LinkedList

{

private:

Node *head;

public:

LinkedList(){

head = NULL;

}

void insert_begin(int newKey);

void insert_end(int newKey);

int negativeSum();

bool deleteAtIndex(int index);

bool deleteAtHead();

void printList();

};

void LinkedList::insert_begin(int newKey){

//1. ALLOCATE NODE

Node* newNode = new Node;

//2. PUT IN THE DATA

newNode->key = newKey;

//3. Make next of newNode as head

newNode->next = head;

//4. Change the head to newNode

head = newNode;

}

void LinkedList::insert_end(int newKey){

//1. ALLOCATE NODE

Node* newNode = new Node;

//2. PUT IN THE DATA

newNode->key = newKey;

//3. Make next of newNode as NULL

newNode->next = NULL;

//4. Check if head is not Null

if(head == NULL){

head = newNode;

return;

}

//4. Traverse the LinkedList till end

Node* temp = head;

while(temp->next != NULL){

temp = temp->next;

}

temp->next = newNode;

return;

}

//TODO

int LinkedList::negativeSum(){

if(head == NULL)

return 0;

int total = 0;

int count = 0;

// TODO Complete this function

Node *pres = head;

while(pres != NULL){

if(pres->key < 0 ){

total = total + pres->key;

count = count + 1;

}

pres = pres->next;

}

cout<<"There is(are) "<<count<<" negative number(s) in the List"<<endl;

return total;

}

// Use deleteAtHead to delete the first item in the list

bool LinkedList::deleteAtHead()

{

bool isDeleted = false;

if(head == NULL){

cout<< "List is already empty"<<endl;

return isDeleted;

}

Node *temp = head;

head = temp->next;

delete temp;

isDeleted = true;

return isDeleted;

}

//TODO

bool LinkedList::deleteAtIndex(int n)

{

bool isDeleted = false;

if(head == NULL){

cout<< "List is already empty"<<endl;

return isDeleted;

}

Node *pres = head;

Node *prev = NULL;

//TODO Complete this function

//isDeleted = true;

// If head needs to be removed

if (n == 0)

{

return deleteAtHead();

}

for (int i=0; pres!=NULL && i<n-1; i++)

pres = pres->next;

if (pres == NULL || pres->next == NULL)

return false;

Node *next = pres->next->next;

free(pres->next); // Free memory

pres->next = next;

isDeleted = true;

return isDeleted;

}

void LinkedList::printList(){

Node* temp = head;

while(temp->next != NULL){

cout<< temp->key <<" -> ";

temp = temp->next;

}

cout<<temp->key<<endl;

}

int main()

{

LinkedList li;

cout<<"Adding nodes to List:"<<endl;

// 2

li.insert_begin(2);

li.printList();

// -1->2

li.insert_begin(-1);

li.printList();

// -1->2->-7

li.insert_end(-7);

li.printList();

// -1->2->-7->10

li.insert_end(10);

li.printList();

// -1->2->-7->10->3

li.insert_end(3);

li.printList();

cout<<endl;

cout<<"Running delete function."<<endl;

/*******************************

Silver Problem - Implement the deleteAtIndex function

********************************/

cout<<"Deleting node at index:"<<endl;

if(!li.deleteAtIndex(3))

{

cout<<"Delete failed!"<<endl;

}

li.printList();

cout<<endl;

if(!li.deleteAtHead())

{

cout<<"Delete failed!"<<endl;

}

li.printList();

cout<<endl;

cout<<"Get the sum of negatives"<<endl;

/*******************************

Gold Problem - Implement the negativeSum function

********************************/

int negsum;

negsum = li.negativeSum();

cout<<"Sum of all the negative elements is "<<negsum<<endl;

}

================================
See Output


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