std::advance

template< class InputIt, class Distance >
void advance( InputIt& it, Distance n );

template< class InputIt, class Distance >
constexpr void advance( InputIt& it, Distance n );

Increments given iterator it by n elements.

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

Parameters

Return value

(none).

Complexity

Linear.

However, if InputIt additionally meets the requirements of RandomAccessIterator, 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';
}

4

See also