Can I use new in class definition?

northfly (229)
I want to put the new in a switch case structure

like:
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Boundary_t *B;

switch(kind) {
case Dirichlet:
    B=new Dirichlet_t();
    break;
case Neumann:
    B=new Neumann_t();
    break;
case Cauchy:
    B=new Cauchy_t();
    break;
}


Never used a new in class definition, and feel strange by using new in here. so ask, thank you!
JLBorges (13770)
Yes.

Make sure that Boundary_t has a virtual destructor.

And ideally use a smart pointer instead of a raw pointer.

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#include <memory>

struct Boundary_t { virtual ~Boundary_t() {} /* ... */ } ;
struct Dirichlet_t : Boundary_t { /* ... */ };
struct Neumann_t : Boundary_t { /* ... */ };
struct Cauchy_t : Boundary_t { /* ... */ };

enum kind_t { Dirichlet, Neumann, Cauchy };

std::unique_ptr<Boundary_t> create( kind_t kind )
{
    Boundary_t* boundary = nullptr ;

    switch(kind)
    {
        case Dirichlet:
            boundary = new Dirichlet_t();
            break;
        case Neumann:
            boundary = new Neumann_t();
            break;
        case Cauchy:
            boundary = new Cauchy_t();
    }

    return std::unique_ptr<Boundary_t>(boundary) ;
}

int main()
{
    auto ptr = create(Neumann) ;

    // ....
}
closed account (Dy7SLyTq)
and also just know that its only possible in c++11 compliant compilers. otherwise it would have to be in a constructor
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