LinkedList example

#include <iostream>
using namespace std;

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

void addToHead(struct Node* &initialHead, int newHeadValue);
void displayList(struct Node* head);
void addToTail(struct Node* initialNode, int tailValue);
int getSize(struct Node* head);
void addAtPosition(struct Node* head, int position, int valueToBeAdded);

int main()
{
    struct Node* head = NULL; // Head-ul listei, primul element din lista! NU TE ATINGE DE EL decat daca iti cere programul.

    // alocare dinamica: (<tipul elementului unde vei stoca date>)malloc(sizeof(<tipul elementului>))
    head = (struct Node*)malloc(sizeof(struct Node));
    head->data = 6;

    addToHead(head, 1);
    addToHead(head, 4);
    addToTail(head, 45);
    addToHead(head, 15);
    addToTail(head, 12);

    displayList(head);
    // 15 4 1 6 45 12
    cout << "-------------------\n\n\n";

    addAtPosition(head, 3, 999);
    displayList(head);
    // 15 4 999 1 6 45 12
    cout << "Our list has: " << getSize(head) << " elements";
    return 0;
}

void addAtPosition(struct Node* head, int position, int valueToBeAdded) {
    int linkedListSize = getSize(head);
    if (position > linkedListSize) {
        cout << "There are fewer elements in the list, compared to the position";
    } else {
        if (position == 1) {
            addToHead(head, valueToBeAdded);
        } else {
            int currentPosition = 1;
            struct Node* currentNode = head;
            while(currentPosition+1 < position) {
                currentPosition++;
                currentNode= currentNode->next;
            }
            struct Node* nodeToBeAdded = (struct Node*) malloc(sizeof(struct Node));
            nodeToBeAdded->data = valueToBeAdded;

            nodeToBeAdded->next = currentNode->next;
            currentNode->next = nodeToBeAdded;
        }
    }

}

void addToHead(struct Node* &initialHead, int newHeadValue) {
    struct Node* newHead = (struct Node*)malloc(sizeof(struct Node));
    newHead->data = newHeadValue;
    newHead->next = initialHead;
    initialHead = newHead;
}

void addToTail(struct Node* initialNode, int tailValue) {
    if(initialNode == NULL) {
        addToHead(initialNode, tailValue);
    } else {
        struct Node* tempNode = initialNode;
        while(tempNode->next != NULL) {
            tempNode = tempNode->next;
        }
        struct Node* tail = (struct Node*) malloc(sizeof(struct Node)); // Dynamic memory allocation
        tail->data = tailValue;
        // Tempnode will hold the last node
        tempNode->next = tail;
        tail->next = NULL;
    }
}


int getSize(struct Node* head) {
    if (head == NULL) return 0;
    int size = 0;
    struct Node* tempHead = head;
    while(tempHead != NULL) {
        size++; // whatever operation u want
        tempHead = tempHead->next;
    }
    return size;
}

void displayList(struct Node* head){
    if (head == NULL) {
        // List is empty
        cout << "List is empty";
    } else {
        struct Node* tempHead = head;

        while (tempHead != NULL) {
            cout << tempHead->data;
            if (tempHead->next != NULL) {
                cout<< "->";
            }
            tempHead = tempHead->next;
        }
        cout << endl;
    }
}