“Std Distance” Ответ

Std Distance

// Calculates the number of elements between first and last.

#include <iterator>     									// std::distance
#include <vector>     										// std::vector
#include <algorithm>   							// Just if you use std::find

vector<int> arr = {2,5,3,8,1};
int size = std::distance(arr.begin(), arr.end()); 			// 5

auto it = std::find(arr.begin(), arr.end(), 8);
int position = std::distance(arr.begin(), it); 				// 3