C++: Initialize template variable in struct

  c++, constructor, struct, templates

fellow stackoverflowers. I’m working on a simple university assignment but have run into a problem I can’t seem to wrap my head around to solve. I’m new to C++ and I’m learning now that implementing generics is not as straightforward in C++ as it is in Java. Inside my LinkedList class there is a struct Node:

struct Node {
    T data;
    Node *next;
}; // Node

Simple enough. And when I create a list of integers in my main.cpp, the implementation functions as it should.

int main() {
    LinkedList<int> integers;
    integers.append(1);
    integers.append(2);
    integers.append(3);
    // append, prepend, get, insert, and remove 
    // functions all work as they should.
} // main

I also have a Passenger class. The problem occurs when I attempt to create a list of Passenger instances.

int main() {
    LinkedList<Passenger> passengers;
    Passenger passenger1("LastName1", "FirstName1", 0);
    Passenger passenger2("LastName2", "FirstName2", 1);
    passengers.append(passenger1);
    passengers.append(passenger2);
} // main

The error messages read exactly as follows:

./LinkedList.hpp:21:10: error: implicit default constructor 
for 'LinkedList<Passenger>::Node' must explicitly initialize 
the member 'data' which does not have a default constructor

./LinkedList.cpp:26:23: note: in implicit default constructor 
for 'LinkedList<Passenger>::Node' first required here:
    Node *newNode = new Node;

The append function in the LinkedList class is the following:

template<class T>
void LinkedList<T>::append(T data) {
    Node *newNode = new Node;
    newNode->data = data;
    newNode->next = NULL;
    if (head == NULL) {
        newNode->next = head;
        this->head = newNode;
    } else {
        Node *ptr = head;
        while (ptr->next != NULL) {
           ptr = ptr->next;
        } // while
        ptr->next = newNode;
    } // if
    length++;
} // append

Thank you so much to anyone who helps me out here!

Source: Windows Questions C++

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