Queue management part 4

Question

It's time to update your Queue management system. The previous version supports only integer numbers and we need to support more types, such as strings, to store customer names in the queue.
Transform the given Queue class to a class template, which can work with different data types.
Please explain the code below thanks

Answer 1

#include <iostream>
using namespace std;
template <class T>
class Queue {
int size;
T* queue;
public:
Queue() {
size = 0;
queue = new T[100];
}
void add(T data) {
queue[size] = data;
size++;
}
void remove() {
if (size == 0) {
cout << "Queue is empty"<<endl;
return;
}
else {
for (int i = 0; i < size - 1; i++) {
queue[i] = queue[i + 1];
}
size--;
}
}
void print() {
if (size == 0) {
cout << "Queue is empty"<<endl;
return;
}
for (int i = 0; i < size; i++) {
cout<<queue[i]<<" <- ";
}
cout << endl;
}
Queue operator+(Queue &obj) {
Queue res;
for(int i=0;i<this->size;i++) {
res.add(this->queue[i]);
}
for(int i=0;i<obj.size;i++) {
res.add(obj.queue[i]);
}
return res;
}
};
int main() {
Queue<int> q1;
q1.add(42); q1.add(2); q1.add(8); q1.add(1);
q1.print();
Queue<string> q2;
q2.add("Dave"); q2.add("John"); q2.add("Amy");
q2.print();
return 0;
}

Answer 2

#include <iostream>
using namespace std;
class Queue {
int size;
int* queue;
public:
Queue() {
size = 0;
queue = new int[100];
}
void add(int data) {
queue[size] = data;
size++;
}
void remove() {
if (size == 0) {
cout << "Queue is empty"<<endl;
return;
}
else {
for (int i = 0; i < size - 1; i++) {
queue[i] = queue[i + 1];
}
size--;
}
}
void print() {
if (size == 0) {
cout << "Queue is empty"<<endl;
return;
}
for (int i = 0; i < size; i++) {
cout<<queue[i]<<" <- ";
}
cout << endl;
}
Queue operator+(Queue &obj) {
Queue res;
for(int i=0;i<this->size;i++) {
res.add(this->queue[i]);
}
for(int i=0;i<obj.size;i++) {
res.add(obj.queue[i]);
}
return res;
}
};
int main() {
Queue<int> q1;
q1.add(42); q1.add(2); q1.add(8); q1.add(1);
q1.print();
Queue<string> q2;
q2.add("Dave"); q2.