What happens if you increment an iterator that is equal to the end iterator of an STL container

Question

What if I increment an iterator by 2 when it points onto the last element of a vector? In this question asking how to adjust the iterator to an STL container by 2 elements t

Answer 1

You could also do more comparisons in your for statement:

for( vector::iterator it = vec.begin(); it != vec.end() && it+1 != vec.end(); it+=2 ) {
    //manipulate the element through the iterator here
}

I don't know how this would perform vs Kostas's suggestion, but it feels like it would be better for a small increment. Of course it would be pretty unmaintainable for a large increment since you need a check for each, but it is another option.

I would definitely avoid it if at all possible. If you really need to increment by 2 values at a time, then consider having a vector of std::pair or a vector of a struct with 2 elements.