iterator

[nss]

I have an iterator that is pointing to a certain element. I want to overwrite this element with the next one following it. *I is the current element. But if I do ++I to get to the next element I lose my place.... I dont think *I = *(++I) is quite going to do it. (what would this do anyways? ) :confused: thanks, ns

[Michael Dunn]

Just copy it :) iterator i2 = i; *++i2 = *i; --Mike-- Personal stuff:: Ericahist | Homepage Shareware stuff:: 1ClickPicGrabber | RightClick-Encrypt CP stuff:: CP SearchBar v2.0.2 | C++ Forum FAQ ---- "Just because the box has 2 gigabytes of memory doesn't mean you get to use it all!"   -- Rico Mariani, CLR perf guy

[nss]

Thanks!!!

[Jorgen Sigvardsson]

Or: *I = *(I + 1);. -- Unser Tanz ist so wild! Ein neuer böser Tanz. Alle gegen Alle!

[Nemanja Trifunovic]

Only if I is a random-access iterator. ;)

[Jorgen Sigvardsson]

Yes, you are right. I thought forward iterator would be ok. I guess one will have to use std::advance instead then. But I'll have to copy the iterator, as std::advance mutates the iterator (passed by reference) :| But I guess one could always do

template <typename Iterator, typename Distance>
Iterator my_advance(const Iterator& i, Distance d) {
Iterator tmp = i;
std::advance(tmp, d);
return tmp;
}

and then

*I = *(my_advance(I, 1));

If the compiler is smart and inlines the function, there's no overhead penalty. -- Unser Tanz ist so wild! Ein neuer böser Tanz. Alle gegen Alle!