Using classes, constructors, destructors, and pointers in C++

Running

Source Code

main.cpp

#include <iostream>
#include <sstream>
using namespace std;

class Set
{
  public:
    Set();
    void add(int n);
    bool contains(int n) const;
    int get_size() const;
    void display();
    ~Set();
    Set(const Set& other_set);
    Set& operator=(const Set& other_set);
  private:
    int* elements;
    int size;
};

Set::Set()
{
  cout << "Enter # of integers: ";
  cin >> size;
  elements = new int[size];
  for (int x = 0; x < size; x++)
  {
    cout << "Enter integer " << x << ": ";
    cin >> *(elements + x); 
  }
}

void Set::add(int n)
{
  int* copy;
  for (int x = 0; x < size; x++)
  {
    copy[x] = elements[x];
  }
  elements = new int[size + 1];
  for (int x = 0; x < size; x++)
  {
    elements[x] = copy[x];
  }
  size++;
  elements[size - 1] = n;
}

bool Set::contains(int n)const
{
  bool has = false;
  for (int x = 0; x < size; x++)
  {
    if (elements[x] == n) has = true;
  }
  return has;
}

int Set::get_size() const
{
  return size;
}

void Set::display()
{
  for (int x = 0; x < size; x++)
  {
    cout << "\nElement " << x << " = " << elements[x];
  }
}

Set::~Set()
{
  delete elements;
  elements = NULL;
}

Set::Set(const Set& other_set)
{
  size = other_set.size;
  elements = new int[size];
  copy(other_set.elements, other_set.elements + size, elements);
}

Set& Set::operator=(const Set& other_set)
{
  if (&other_set != this)
  {
    size = other_set.size;
    elements = new int[size];
    copy(other_set.elements, other_set.elements + size, elements);
  }
  return *this;
}
 
int main(int argc, char** argv)
{
  Set x;
  x.display();
  x.add(5);
  cout << "\n\nNew set with 5 added:\n";
  x.display();
  cout << "\n\nDoes it have a 3? ";
  if (x.contains(3))
  {
    cout << "yes";
  }
  else
  {
    cout << "no";
  }
  stringstream ss;
  ss << x.get_size();
  cout << "\n\nSize of array: " << ss.str();
  Set y = x;
  cout << "\n\nMade Set y = x.  This is values of Set y:\n";
  y.display();
  return 0;
}