Re: pointer to a vector
"A" <a@a.a> wrote in news:ldgj2i$2gc$1@gregory.bnet.hr:
There are 2 vectors each one having a structure
struct MyStruct
{
int a;
std::string b;
}
std::vector<MyStruct> v1;
std::vector<MyStruct> v2;
Now I want a pointer to which one I will use... v1 or v2
std::vector<MyStruct> *v = (condition)? &v1 : &v2;
Finally I access it using:
for (unsigned i = 0; i < v->size(); i++)
{
v->operator[](i).a = i + 1;
}
You can also use references:
std::vector<MyStruct> & v = (condition)? v1 : v2;
....
v[i].a = i+1;
My lack of understanding here is:
a) does the above *v needs to be deleted? Isn't it just a pointer
variable? Or it works differently when it points to a vector? Just to
be clear, I don't actually need to delete v1 or v2. I just need to
cleanup *v if required.
No, as a rule of thumb, if your code does not contain 'new' then there is
no need for 'delete' either (and this is a good thing). Any dynamically
allocated memory is maintained and released by the std::vector objects
internally.
b) what's the heap or stack or difference or advantage of them in
relation to the above?
std::vector automatically stores the stuff in the right place, you do not
need to worry about this. Just avoid raw arrays and 'new' (as you have
done so far) and you should be fine.
Cheers
Paavo
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