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std::advance

Defined in header `<iterator>`
template< class InputIt, class Distance > void advance( InputIt& it, Distance n );		(until C++17)
template< class InputIt, class Distance > constexpr void advance( InputIt& it, Distance n );		(since C++17)

Increments given iterator it by n elements.

If n is negative, the iterator is decremented. In this case, InputIt must meet the requirements of LegacyBidirectionalIterator, otherwise the behavior is undefined.

Parameters

it	-	iterator to be advanced
n	-	number of elements `it` should be advanced
Type requirements
-`InputIt` must meet the requirements of LegacyInputIterator.

Return value

(none).

Complexity

Linear.

However, if InputIt additionally meets the requirements of LegacyRandomAccessIterator, complexity is constant.

Notes

The behavior is undefined if the specified sequence of increments or decrements would require that a non-incrementable iterator (such as the past-the-end iterator) is incremented, or that a non-decrementable iterator (such as the front iterator or the singular iterator) is decremented.

Example

#include <iostream>
#include <iterator>
#include <vector>
 
int main() 
{
    std::vector<int> v{ 3, 1, 4 };
 
    auto vi = v.begin();
 
    std::advance(vi, 2);
 
    std::cout << *vi << '\n';
}

Output: