1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // <deque>
10 
11 // void pop_front()
12 
13 //  Erasing items from the beginning or the end of a deque shall not invalidate iterators
14 //  to items that were not erased.
15 
16 #include <deque>
17 #include <cassert>
18 
19 template <typename C>
20 void test(C c)
21 {
22     typename C::iterator it1 = c.begin() + 1;
23     typename C::iterator it2 = c.end() - 1;
24 
25     c.pop_front();
26 
27     typename C::iterator it3 = c.begin();
28     typename C::iterator it4 = c.end() - 1;
29     assert(  it1 ==   it3);
30     assert( *it1 ==  *it3);
31     assert(&*it1 == &*it3);
32     assert(  it2 ==   it4);
33     assert( *it2 ==  *it4);
34     assert(&*it2 == &*it4);
35 }
36 
37 int main(int, char**)
38 {
39     std::deque<int> queue;
40     for (int i = 0; i < 20; ++i)
41         queue.push_back(i);
42 
43     while (queue.size() > 1)
44     {
45         test(queue);
46         queue.pop_back();
47     }
48 
49   return 0;
50 }
51