How to increment an iterator by 2?

Question

Can anybody tell me how to increment the iterator by 2?

iter++ is available - do I have to do iter+2? How can I achieve this?

Answer 1

We can use both std::advance as well as std::next, but there's a difference between the two.

advance modifies its argument and returns nothing. So it can be used as:

vector v;
v.push_back(1);
v.push_back(2);
auto itr = v.begin();
advance(itr, 1);          //modifies the itr
cout << *itr<

next returns a modified copy of the iterator:

vector v;
v.push_back(1);
v.push_back(2);
cout << *next(v.begin(), 1) << endl;    //prints 2