removing element from vector while iterating c 2b 2b

1#include <iostream>
2#include <vector>
3#include <algorithm>
4 
5int main()
6{
7    std::vector<int> v = { 1, 2, 3, 4, 5, 6 };
8 
9    auto it = v.begin();
10    while (it != v.end())
11    {
12        // specify condition for removing element; in this case remove odd numbers
13        if (*it & 1) {
14            // erase() invalidates the iterator, use returned iterator
15            it = v.erase(it);
16        }
17        // Notice that iterator is incremented only on the else part (why?)
18        else {
19            ++it;
20        }
21    }
22 
23    for (int const &i: v) {
24        std::cout << i << ' ';
25    }
26 
27    return 0;
28}
29