Dynamically Allocating Arrays with Smart Pointers

To dynamically allocate an array with a smart pointer, you can use std::unique_ptr with an array type:

1#include <memory>
2#include <iostream>
3
4int main() {
5  std::unique_ptr<int[]> Array{new int[5]{
6    1, 2, 3, 4, 5}};
7
8  for (int i = 0; i < 5; i++) {
9    std::cout << Array[i] << ' ';
10  }
11}

11 2 3 4 5

Note that we use int[] as the template argument to std::unique_ptr, not just int. This tells the smart pointer that it's managing an array, not a single object.

When the unique_ptr goes out of scope, it will automatically call delete[] on the managed array.

If you need to specify the size of the array at runtime, you can use std::make_unique:

1#include <memory>
2#include <iostream>
3
4int main() {
5  int size{5};
6  std::unique_ptr<int[]> Array{
7    std::make_unique<int[]>(size)};
8
9  for (int i = 0; i < size; i++) {
10    Array[i] = i + 1;
11    std::cout << Array[i] << ' ';
12  }
13}

11 2 3 4 5

Note that when using std::make_unique, we don't use the new keyword.

Also remember that std::unique_ptr<int[]> does not keep track of the size of the array. You need to track that separately if needed.