How to make 2d c-style arrays with unique_ptr?

Question

To create a simple array i'd do!!
std::unique_ptr<int[]> arr(new int[100]);

How can i create a 100*100 2d array using a unique ptr??

Answer 1

Like you would do with classic heap arrays:

int ** a = new int*[100];
for (int i = 0; i < 100; i++)
{
a[i] = new int[100];
}

the unique_ptr just acts like your regular old pointer (just with fancy syntax)

std::unique_ptr<std::unique_ptr<int[]>[]> arr(new std::unique_ptr<int[]>[100]);
for (int i = 0; i < 100; i++)
{
arr[i] = std::unique_ptr<int[]>(new int[100]);
}

Follow up question: why tho?