CODEWITHSUNDEEP
c++arraysmultidimensional-arrayconstructor
mskuratowski
mskuratowski

Reputation: 4124

Constructor - memory allocation failed

I have a constructor which create and empty A with r rows and c columns

A::A(int r, int c)
    : row(r), column(c), e(new int[r*c])
{
    for (int i = 0; i < r*c; i++)
    {
        e[i] = 0;
    }
}

I am wondering if a memory allocation will failed, it will still initialize row and column with non-zero values. How can I prevent it ?

Upvotes: 1

Views: 161

Answers (1)

Baum mit Augen
Baum mit Augen

Reputation: 50061

If new fails to allocate memory, it throws an instance of std::bad_alloc, i.e. an exception.

If your constructor fails, all already completely constructed members and bases are destroyed and no valid instance of your type is created.

So your r and c have no value at all if you leave your constructor via an exception because they do not exist.

You will indeed never even reach the loop you seem to worry about.

Upvotes: 9

Related Questions