Pointing to elements in a vector.

[anotherghost]

Hi,

So I've got 3 structs - track, top_hit, and bot_hit. A track is essentially just a pointer to a top_hit and a bot_hit with some member functions to analyse them.

// Constructor for track:
track(top_hit *topHit_i, bot_hit *botHit_i) : topHit(topHit_i), botHit(botHit_i) {
x_delay = botHit->x_time - topHit->x_time;
y_delay = botHit->y_time - topHit->y_time;
}

In my main testing routine I make a top_hit called bruce and a bot_hit called giles. Then I make a track jerome out of them.

track jerome(&bruce,&giles);
jerome.Show();

This does exactly what I want it to do.

Now I am trying to convert this to work with a vector of hits as that ultimately will be condusive to what I want (but mostly because I need to learn how to use vectors).

I make my vector of hits, and test it...

vector <hit> hits;
hits.push_back(bruce);
hits.push_back(giles);

hits[0].Show();
hits[1].Show();

...which works fine.

Now I try to make jerome again, under a more casual name.

track jerry(&hits[0],&hits[1]);

This does not work. I've also tried track jerry(hits[0],hits[1]) and jerry(*hits[0],*hits[1]) but jerry is not having any of those things. I suspect this is because I am self taught and do not know how to use pointers very well.

Can anybody help me point at these vector elements properly?

[LB]

You're using polymorphism, right? Well, casting of a derived type to base type is implicit, but you have to explicitly cast the base to a derived type.

[anotherghost]

Hm ok. So do I need two separate top_hit and bot_hit vectors? Or do I need to make a different constructor for track?

[LB]

You can still use one vector, you just need to have a way that you can tell if the hit you are accessing is a top hit or bottom hit and then cast them to the correct types to pass to your tack constructor.