new int with no overwrite

[Morapoly]

I have a int* that named arr and have a function that called in main(); this function named push_back that add a int to arr; I also have a function named pop_back that delete arr[the_last_member].
This is my project:
***************************************************************************
main.cpp :

#include<iostream>
#include "vector.h"

using std::cout;
using std::endl;

int main()
{
vector v;
v.push_back(0);
v.push_back(1);
v.pop_back(); //this delete arr[the_last_member]
return 0;
}

*********
vector.h:

#pragma once
#include<iostream>

class vector
{
public:
vector();
void push_back(int n);
void pop_back();
~vector();
int* arr;
int static cnt;
};

**********
vector.cpp:

#include "vector.h"



vector::vector()
{
}

void vector::push_back(int n)
{
int static cnt{};
cnt++;
arr = new int[cnt];
arr[cnt - 1] = n;
}

void vector::pop_back()
{
cnt--;
arr = new int[cnt];
}


vector::~vector()
{
delete[] arr;
}

but in this program old members of arr will be deleted.
How can I resolve it?

[ne555]

actually, they aren't being deleted, they are simply lost, drifting in the memory sea.

consider to move them, one by one, to their new destination.