How to dynamically increase the array size?

Question

I\'ve been trying to make a program that adds 2 arrays of different size. But I would like to know to to dynamically increase the array size capacity? Ex: array[4] then upgrade

Answer 1

   int* newArr = new int[new_size];
   std::copy(oldArr, oldArr + std::min(old_size, new_size), newArr);
   delete[] oldArr;
   oldArr = newArr;