Code is complete, I just need an explanation on how this code functions. #include using namespace std; class node {     public:     double data;     node* next; }; node* head; void addData(double val) {     node *n = new node;     n->data=val;     n->next=NULL;     if(head==NULL)     {         head=n;     }     else     {         node *ptr=head;         while(ptr->next!=NULL)         {             ptr=ptr->next;         }         ptr->next=n;     } } void addBack(double x) {     node *n = new node;     n->data=x;     n->next=NULL;     node *ptr=head;     while(ptr->next!=NULL)     {         ptr=ptr->next;     }     ptr->next=n; } void display() {     node *ptr=head;     while(ptr!=NULL)     {         cout<data<<", ";         ptr=ptr->next;     }     cout<

Code is complete, I just need an explanation on how this code functions.

#include <iostream>
using namespace std;
class node
{
    public:
    double data;
    node* next;
};
node* head;
void addData(double val)
{
    node *n = new node;
    n->data=val;
    n->next=NULL;
    if(head==NULL)
    {
        head=n;
    }
    else
    {
        node *ptr=head;
        while(ptr->next!=NULL)
        {
            ptr=ptr->next;
        }
        ptr->next=n;
    }
}

void addBack(double x)
{
    node *n = new node;
    n->data=x;
    n->next=NULL;
    node *ptr=head;
    while(ptr->next!=NULL)
    {
        ptr=ptr->next;
    }
    ptr->next=n;
}

void display()
{
    node *ptr=head;
    while(ptr!=NULL)
    {
        cout<<ptr->data<<", ";
        ptr=ptr->next;
    }
    cout<<endl;
}

int main() 
{
    head=NULL;
    addData(4.7);
    addData(12.8);
    addData(14.7);
    addData(16.2);
    cout<<"Linked List"<<endl;
    display();
    addBack(56.9);
    cout<<"After adding node with data 56.9 to the back of linked list:";
    display();
    addBack(11.9);
    cout<<"After adding node with data 11.9 to the back of linked list:";
    display();
    addBack(34.9);
    cout<<"After adding node with data 34.9 to the back of linked list:";
    display();
 return 0;
}