HOw to dynamicaaly grow an array in C++ code example

Example 1: declare dynamic array c++

int main()
{
  int size;

  std::cin >> size;

  int *array = new int[size];

  delete [] array;

  return 0;
}

Example 2: resizing dynamic array c++

void resize() {
    size_t newSize = size * 2;
    int* newArr = new int[newSize];

    memcpy( newArr, arr, size * sizeof(int) );

    size = newSize;
    delete [] arr;
    arr = newArr;
}