Memory management in allocating 2-D array

Question

I have allocated a two dimensional array using the following code:

// Dynamic allocation
        int **matrix=new int*[n];
        for(int i=0;i

        

Answer 1

for(int i=0;i<n;i++)
{
    delete [] matrix[i];
}

delete [] matrix

You need to delete each of the internal arrays and then delete the array.

As has been suggested in a comment. A safer way of doing this would be to use standard containers such as std::vector. You could do something like this then:

std::vector<std::vector<int>> matrix;

This would give you a two dimensional array but you would not have to handle the cleanup.

Answer 2

"What is the correct way of doing it?"

Using standard containers like e.g. std::vector<std::vector<int>> or std::array<std::array<int,N>,N> (supposed N is already known at compile time) is the correct way.
You don't use new()/new[] and delete/delete[] in 1st place (besides rare valid use cases).

If you're sure you have such case, you delete in exactly the reverse order as you were allocating using new[]. delete [][]; isn't valid syntax, as the compiler already told you.