std::prev
From cppreference.com
                    
                                        
                    
                    
                                                            
                    | Defined in header  <iterator> | ||
| template< class BidirIt > BidirIt prev( BidirIt it,  | (since C++11) | |
Return the nth predecessor of iterator it.
| Contents | 
[edit] Parameters
| it | - | an iterator | 
| n | - | number of elements it should be descended | 
| Type requirements | ||
| - BidirItmust meet the requirements ofBidirectionalIterator. | ||
[edit] Return value
The nth predecessor of iterator it.
[edit] Possible implementation
| template<class BidirIt> BidirIt prev(BidirIt it, typename std::iterator_traits<BidirIt>::difference_type n = 1) { std::advance(it, -n); return it; } | 
[edit] Example
Run this code
#include <iostream> #include <iterator> #include <vector> int main() { std::vector<int> v{ 3, 1, 4 }; auto it = v.end(); auto pv = std::prev(it, 2); std::cout << *pv << '\n'; }
Output:
1
[edit] See also
| (C++11) | increment an iterator (function) | 
| advances an iterator by given distance (function) | 


