Question

Modify this linked list code to work with string. Insert the following items into the list and display the list. The items are: Pepsi, Coke, DrPepper, Sprite, Fanta. Insert them in that order. Display the list. Then delete DrPepper and redisplay the list. Then insert 7-UP and redisplay the list. Then append Water and redisplay the list. c++

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#include <iostream>

using namespace std;

class ListNode {
public:
    int value;
    ListNode *next;

    ListNode(int nodeValue) {
      value = nodeValue;
      next = nullptr;
    }
};

class LinkedList {
private:
    ListNode *head;
public:
    LinkedList() { head = nullptr; }
    //~LinkedList(); // destructor

    void appendNode(int);
    void insertNode(int);
    void deleteNode(int);
    void displayList() const;

};

void LinkedList::appendNode(int newValue) {
ListNode *newNode;
ListNode *nodePtr;

newNode = new ListNode(newValue);

if (!head) {
     head = newNode;
}
else {
    nodePtr = head;
    while (nodePtr->next) {
        nodePtr = nodePtr->next;
    }
    nodePtr->next = newNode;
}
}

void LinkedList::displayList() const {
ListNode *nodePtr;
nodePtr = head;
while (nodePtr) {
    cout << nodePtr->value << " ";
    nodePtr = nodePtr->next;
}
}

void LinkedList::insertNode(int newValue) {
ListNode *newNode;
ListNode *nodePtr;
ListNode *previousNode = nullptr;

newNode = new ListNode(newValue);

if (!head) {
    head = newNode;
    newNode->next = nullptr;
}
else {

    nodePtr = head;
    /*cout << "nodeptr value when assigned as head: " <<
        nodePtr->value << endl;*/
    previousNode = nullptr;
    while (nodePtr != nullptr && nodePtr->value < newValue) {
        previousNode = nodePtr;
        nodePtr = nodePtr->next;
    }
    if (previousNode == nullptr) {
        head = newNode;
        newNode->next = nodePtr;
    }
    else {
        previousNode->next = newNode;
        newNode->next = nodePtr;
    }
}

}

void LinkedList::deleteNode(int searchValue) {
ListNode *nodePtr;
ListNode *previousNode;

if (!head) {
    return;
}
if (head->value == searchValue) {
    nodePtr = head->next;
    delete head;
    head = nodePtr;
}
else {
    nodePtr = head;
    while (nodePtr != nullptr && nodePtr->value != searchValue) {
        previousNode = nodePtr;
        nodePtr = nodePtr->next;
    }
    if (nodePtr) {
        previousNode->next = nodePtr->next;
        delete nodePtr;
    }
}
}

int main()
{
    LinkedList numbers;
    numbers.appendNode(1);
    numbers.appendNode(2);
    numbers.appendNode(4);
    numbers.displayList();
    cout << endl << endl;
    numbers.insertNode(3);
    numbers.displayList();
    cout << endl << endl;
    numbers.deleteNode(2);
    numbers.displayList();
    numbers.appendNode(6);
    cout << endl << endl;
    numbers.displayList();
    numbers.insertNode(5);
    cout << endl << endl;
    numbers.displayList();
    numbers.insertNode(2);
    cout << endl << endl;
    numbers.displayList();
    return 0;
}

Answer 1

Please find the answer below.
Please do comments in case of any issue. Also, don't forget to rate the question. Thank You So Much.

#include <iostream>
#include <string>

using namespace std;

class ListNode {
public:
   string value;
   ListNode *next;

   ListNode(string nodeValue) {
       value = nodeValue;
       next = nullptr;
   }
};

class LinkedList {
private:
   ListNode *head;
public:
   LinkedList() { head = nullptr; }
   //~LinkedList(); // destructor

   void appendNode(string);
   void insertNode(string);
   void deleteNode(string);
   void displayList() const;

};

void LinkedList::appendNode(string newValue) {
   ListNode *newNode;
   ListNode *nodePtr;

   newNode = new ListNode(newValue);

   if (!head) {
       head = newNode;
   }
   else {
       nodePtr = head;
       while (nodePtr->next) {
           nodePtr = nodePtr->next;
       }
       nodePtr->next = newNode;
   }
}

void LinkedList::displayList() const {
   ListNode *nodePtr;
   nodePtr = head;
   while (nodePtr) {
       cout << nodePtr->value << " ";
       nodePtr = nodePtr->next;
   }
}

void LinkedList::insertNode(string newValue) {
   ListNode *newNode;
   ListNode *nodePtr;
   ListNode *previousNode = nullptr;

   newNode = new ListNode(newValue);

   if (!head) {
       head = newNode;
       newNode->next = nullptr;
   }
   else {

       nodePtr = head;
       /*cout << "nodeptr value when assigned as head: " <<
nodePtr->value << endl;*/
       previousNode = nullptr;
       while (nodePtr != nullptr && nodePtr->value < newValue) {
           previousNode = nodePtr;
           nodePtr = nodePtr->next;
       }
       if (previousNode == nullptr) {
           head = newNode;
           newNode->next = nodePtr;
       }
       else {
           previousNode->next = newNode;
           newNode->next = nodePtr;
       }
   }

}

void LinkedList::deleteNode(string searchValue) {
   ListNode *nodePtr;
   ListNode *previousNode;

   if (!head) {
       return;
   }
   if (head->value == searchValue) {
       nodePtr = head->next;
       delete head;
       head = nodePtr;
   }
   else {
       nodePtr = head;
       while (nodePtr != nullptr && nodePtr->value != searchValue) {
           previousNode = nodePtr;
           nodePtr = nodePtr->next;
       }
       if (nodePtr) {
           previousNode->next = nodePtr->next;
           delete nodePtr;
       }
   }
}

int main()
{
   LinkedList numbers;
   numbers.appendNode("Pepsi");
   numbers.appendNode("Coke");
   numbers.appendNode("DrPepper");
   numbers.displayList();
   cout << endl << endl;
   numbers.insertNode("Sprite");
   numbers.deleteNode("Fanta");
   numbers.displayList();
   cout << endl << endl;
   numbers.deleteNode("DrPepper");
   numbers.displayList();
   return 0;
}

output