Re: Passing Temporaries to perform non const operations

Altering a temporary is perfectly legal, for example:

std::vector<int> vec(40);
std::vector<int>(4).swap(vec); //legal.

I am trying to get this same functionality, but within an assignment
operator, but can't seem to find a good way to bind the temporary.

For example:

class Foo;
int main()
{
 Foo f;
 f = Foo(20);

}

#include <vector>
class Foo
{
public:
  Foo(int size=0) { m_data.resize(size);}

  // PROBLEM HERE. The temporary can't be bound to a reference to no=

const
  // But if this were 'const reference', the swap function could not
be called using it.
  void operator=(Foo& foo)
  {
    m_data.swap(foo.m_data);
  }
  std::vector<int> m_data;

};

The only work-around I could think of was this ugly code:
void operator=(const Foo& foo)
{
  std::vector<T>* tmpVec = const_cast<std::vector<T>*>(foo.m_data);
  tmpVec->swap(m_data);

}

Any better suggestions?

Thanks,
Joe