Re: const vector<A> vs vector<const A> vs const vector<const A>
On Sep 4, 7:53 pm, Javier <jjeron...@gmail.com> wrote:
thanks for the replies to my questions.
I have one more:
class A
{
public:
m1() const;
m2();
};
is there any difference between
std::vector<const A> v;
const std::vector<A> v;
const std::vector<const A> v;
Yes. The first and third aren't legal. An element of a
container must support assignment, and A const doesn't.
In general, in the standard library, declaring a container to be
const (i.e. your second declaration) means that 1) the topology
(number and order of elements) cannot change, and 2) the value
of the individual elements cannot change.
and, what about:
A a1;
v.push_back(a1);
v[0].m1()
v[0].m2()
in the three cases?
Illegal. As I said above, the declaration of v is illegal in
the first and third cases above. And if v is declared as in the
second case, push_back cannot be used on it. Given something
like:
std::vector< A > const v( 1, A() ) ;
however, v[0].m1() is legal, v[0].m2() no.
--
James Kanze (GABI Software) email:james.ka...@gmail.com
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