1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <deque>
11 
12 // iterator erase(const_iterator f, const_iterator l)
13 
14 //  Erasing items from the beginning or the end of a deque shall not invalidate iterators
15 //  to items that were not erased.
16 
17 
18 #include <deque>
19 #include <cstdint>
20 #include <cassert>
21 
22 template <typename C>
del_at_start(C c,size_t num)23 void del_at_start(C c, size_t num)
24 {
25     typename C::iterator first = c.begin();
26     typename C::iterator last  = first + num;
27     typename C::iterator it1 = last;
28     typename C::iterator it2 = c.end() - 1;
29 
30     c.erase (first, last);
31 
32     typename C::iterator it3 = c.begin();
33     typename C::iterator it4 = c.end() - 1;
34     assert(  it1 ==   it3);
35     assert( *it1 ==  *it3);
36     assert(&*it1 == &*it3);
37     assert(  it2 ==   it4);
38     assert( *it2 ==  *it4);
39     assert(&*it2 == &*it4);
40 }
41 
42 template <typename C>
del_at_end(C c,size_t num)43 void del_at_end(C c, size_t num)
44 {
45     typename C::iterator last  = c.end();
46     typename C::iterator first = last - num;
47     typename C::iterator it1 = c.begin();
48     typename C::iterator it2 = first - 1;
49 
50     c.erase (first, last);
51 
52     typename C::iterator it3 = c.begin();
53     typename C::iterator it4 = c.end() - 1;
54     assert(  it1 ==   it3);
55     assert( *it1 ==  *it3);
56     assert(&*it1 == &*it3);
57     assert(  it2 ==   it4);
58     assert( *it2 ==  *it4);
59     assert(&*it2 == &*it4);
60 }
61 
62 
main()63 int main()
64 {
65     std::deque<int> queue;
66     for (int i = 0; i < 20; ++i)
67         queue.push_back(i);
68 
69     while (queue.size() > 1)
70     {
71         for (size_t i = 1; i < queue.size(); ++i)
72         {
73             del_at_start(queue, i);
74             del_at_end  (queue, i);
75         }
76         queue.pop_back();
77     }
78 }
79