std::next returns an iterator pointing to the element after being advanced by certain no. of positions. It is defined inside the header file
.
It
does not modify its arguments and returns a copy of the argument advanced by the specified amount. If it is a
random-access iterator, the function uses just once operator + or operator - for advancing. Otherwise, the function uses repeatedly the increase or decrease operator (operator ++ or operator --) on the copied iterator until n elements have been advanced.
Syntax:
ForwardIterator next (ForwardIterator it,
typename iterator_traits::difference_type n = 1);
it: Iterator to the base position.
difference_type: It is the numerical type that represents
distances between iterators of the ForwardIterator type.
n: Total no. of positions by which the
iterator has to be advanced. In the syntax, n is assigned
a default value 1 so it will atleast advance by 1 position.
Returns: It returns an iterator to the element
n positions away from it.
Output:
v1 = 1 2 3 4 5 6 7
v2 = 8 9 10 1 2 3 4
How can it be helpful ?
- Advancing iterator in Lists: Since, lists support bidirectional iterators, which can be incremented only by using ++ and - - operator. So, if we want to advance the iterator by more than one position, then using std::next can be extremely useful.
Output:
v1 = 1 2 3 7 8 9
v2 = 4 5 6 1 2 3
Explanation: Here, just look how if we want copy only a selected portion of the list, then we can make use of std::next, as otherwise we cannot use any +=, -= operators with bidirectional iterators supported by lists. So, we used std::next and directly advanced the iterator by three positions.
