int test_iterator_20()
{
// std::reverse_iterator: 反向迭代器
std::vector<int> myvector;
for (int i = 0; i<10; i++) myvector.push_back(i);
typedef std::vector<int>::iterator iter_type;
// ? 0 1 2 3 4 5 6 7 8 9 ?
iter_type from(myvector.begin()); // ^
// ------>
iter_type until(myvector.end()); // ^
//
std::reverse_iterator<iter_type> rev_until(from); // ^
// <------
std::reverse_iterator<iter_type> rev_from(until); // ^
std::cout << "myvector:";
while (rev_from != rev_until)
std::cout << ' ' << *rev_from++; // 9 8 7 6 5 4 3 2 1 0
std::cout << '\n';
return 0;
}
void GameStateManager::cleanup()
{
//unwind state stack in reverse
typedef std::vector<State*>::iterator iter_type;
iter_type from(gameStates.begin());
iter_type until(gameStates.end());
std::reverse_iterator<iter_type> rev_until(from);
std::reverse_iterator<iter_type> rev_from(until);
while (rev_from != rev_until)
{
delete *rev_from++;
}
for (auto& state : hangingStates)
{
delete state;
state = nullptr;
}
//remove all state pointers
gameStates.clear();
hangingStates.clear();
}
