matrix destructor

[Aisthesis]

My destructor works, but I wanted to check to see if it's correct to do it this way. Here's the code first for the default constructor:

template<typename T, int n>
Matrix<T, n>::Matrix()
{
	T** arr = new T*[n];
	for (int i = 0; i < n; ++i)
	{
		arr[i] = new T[n];
	}
	for (int i = 0; i < n; ++i) // rows
	{
		for (int j = 0; j < n; ++j) // columns
		{
			arr[i][j] = 0;	// T must define 0 and 1
		}
	}
	content = arr;
}

Now the destructor:

// destructor
template<typename T, int n>
Matrix<T, n>::~Matrix()
{
	// free memory on each row
	for (int i = 0; i < n; ++i)
	{
		delete [] content[i];
		content[i] = NULL;
	}
	// delete content entirely
	delete [] content;
	content = NULL;
}

correct? it at least seems to me that just delete [] content wouldn't set the individual blocks pointed to back as available memory.

[Salem]

Yes, that's correct.

Assigning pointers to NULL in this context isn't necessary.

But it's a useful habit that could easily save weeks of confusion if you're re-using pointers and make the mistake of trying to use it after it has been freed.

[Aisthesis]

ok, cool, tx!

[cpjust]

I think your constructor should have a try-catch block to delete any memory you've allocated, just in case you get a std::bad_alloc exception in one of your calls to new.